Annual report pursuant to Section 13 and 15(d)

Long-term Debt (Line of Credit) (Details)

v2.4.1.9
Long-term Debt (Line of Credit) (Details) (USD $)
0 Months Ended 12 Months Ended
Oct. 22, 2012
Aug. 19, 2011
Jan. 03, 2015
Dec. 28, 2013
Dec. 29, 2012
Nov. 21, 2014
Aug. 21, 2014
Oct. 22, 2013
Jun. 30, 2010
Line of Credit Facility [Line Items]                  
Variable rate basis     LIBOR            
Revolving Line of Credit [Member]                  
Line of Credit Facility [Line Items]                  
Line of credit, maximum borrowing capacity $ 30,000,000us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_RevolvingCreditFacilityMember
  $ 40,000,000us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_RevolvingCreditFacilityMember
    $ 40,000,000us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_RevolvingCreditFacilityMember
  $ 25,000,000us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_RevolvingCreditFacilityMember
$ 20,000,000us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_RevolvingCreditFacilityMember
Maturity date extension period 1 year 1 year              
Line of credit, increase to limit 5,000,000synl_LineOfCreditFacilityIncreaseInMaximumBorrowingCapacity
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_RevolvingCreditFacilityMember
        15,000,000synl_LineOfCreditFacilityIncreaseInMaximumBorrowingCapacity
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_RevolvingCreditFacilityMember
5,000,000synl_LineOfCreditFacilityIncreaseInMaximumBorrowingCapacity
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_RevolvingCreditFacilityMember
   
Stated interest rate (percent)     1.77%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_RevolvingCreditFacilityMember
2.16%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_RevolvingCreditFacilityMember
2.21%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_RevolvingCreditFacilityMember
       
Unused capacity fee on line of credit (percent)     0.125%us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_RevolvingCreditFacilityMember
           
Line of credit, amount borrowed     884,637us-gaap_LineOfCredit
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_RevolvingCreditFacilityMember
           
Line of credit, remaining availability     39,115,363us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_RevolvingCreditFacilityMember
           
Line of credit, average outstanding amount     2,735,000us-gaap_LineOfCreditFacilityAverageOutstandingAmount
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_RevolvingCreditFacilityMember
19,860,000us-gaap_LineOfCreditFacilityAverageOutstandingAmount
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_RevolvingCreditFacilityMember
11,045,000us-gaap_LineOfCreditFacilityAverageOutstandingAmount
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_RevolvingCreditFacilityMember
       
Line of credit, weighted average interest rate (percent)     1.35%us-gaap_LineOfCreditFacilityInterestRateDuringPeriod
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_RevolvingCreditFacilityMember
1.74%us-gaap_LineOfCreditFacilityInterestRateDuringPeriod
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_RevolvingCreditFacilityMember
1.82%us-gaap_LineOfCreditFacilityInterestRateDuringPeriod
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_RevolvingCreditFacilityMember
       
Interest payments     $ 930,000us-gaap_InterestPaid
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_RevolvingCreditFacilityMember
$ 1,202,000us-gaap_InterestPaid
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_RevolvingCreditFacilityMember
$ 492,000us-gaap_InterestPaid
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_RevolvingCreditFacilityMember