Note 8 - Benefit Plans - The Company's Pension Plan Assets Measured at Fair Value (Details) - USD ($) $ in Thousands	Dec. 30, 2017	Dec. 31, 2016
Total pension plan assets	$ 48,123	$ 42,208
Cash and Cash Equivalents [Member]
Total pension plan assets	404	1,428
Fair Value, Inputs, Level 1 [Member]
Total pension plan assets	9,292	8,638
Fair Value, Inputs, Level 1 [Member] | Cash and Cash Equivalents [Member]
Total pension plan assets	173	476
Fair Value, Inputs, Level 2 [Member]
Total pension plan assets
Fair Value, Inputs, Level 2 [Member] | Cash and Cash Equivalents [Member]
Total pension plan assets
Fair Value, Inputs, Level 3 [Member]
Total pension plan assets
Fair Value, Inputs, Level 3 [Member] | Cash and Cash Equivalents [Member]
Total pension plan assets
Fair Value Measured at Net Asset Value Per Share [Member]
Total pension plan assets	38,831	33,570
Fair Value Measured at Net Asset Value Per Share [Member] | Cash and Cash Equivalents [Member]
Total pension plan assets	231	952
Global Equity Index Fund [Member] | Equity Securities [Member]
Total pension plan assets	7,898	6,321
Global Equity Index Fund [Member] | Fair Value, Inputs, Level 1 [Member] | Equity Securities [Member]
Total pension plan assets
Global Equity Index Fund [Member] | Fair Value, Inputs, Level 2 [Member] | Equity Securities [Member]
Total pension plan assets
Global Equity Index Fund [Member] | Fair Value, Inputs, Level 3 [Member] | Equity Securities [Member]
Total pension plan assets
Global Equity Index Fund [Member] | Fair Value Measured at Net Asset Value Per Share [Member] | Equity Securities [Member]
Total pension plan assets	7,898	6,321
Global Equity GBP Hedge Fund [Member] | Equity Securities [Member]
Total pension plan assets	8,134	6,406
Global Equity GBP Hedge Fund [Member] | Fair Value, Inputs, Level 1 [Member] | Equity Securities [Member]
Total pension plan assets
Global Equity GBP Hedge Fund [Member] | Fair Value, Inputs, Level 2 [Member] | Equity Securities [Member]
Total pension plan assets
Global Equity GBP Hedge Fund [Member] | Fair Value, Inputs, Level 3 [Member] | Equity Securities [Member]
Total pension plan assets
Global Equity GBP Hedge Fund [Member] | Fair Value Measured at Net Asset Value Per Share [Member] | Equity Securities [Member]
Total pension plan assets	8,134	6,406
Philippine Stock [Member] | Equity Securities [Member]
Total pension plan assets	1,031	906
Philippine Stock [Member] | Fair Value, Inputs, Level 1 [Member] | Equity Securities [Member]
Total pension plan assets	1,031	906
Philippine Stock [Member] | Fair Value, Inputs, Level 2 [Member] | Equity Securities [Member]
Total pension plan assets
Philippine Stock [Member] | Fair Value, Inputs, Level 3 [Member] | Equity Securities [Member]
Total pension plan assets
Philippine Stock [Member] | Fair Value Measured at Net Asset Value Per Share [Member] | Equity Securities [Member]
Total pension plan assets
Investment Grade Corporate Bond Funds [Member] | Debt Securities [Member]
Total pension plan assets	6,003	5,372
Investment Grade Corporate Bond Funds [Member] | Fair Value, Inputs, Level 1 [Member] | Debt Securities [Member]
Total pension plan assets	6,003	5,372
Investment Grade Corporate Bond Funds [Member] | Fair Value, Inputs, Level 2 [Member] | Debt Securities [Member]
Total pension plan assets
Investment Grade Corporate Bond Funds [Member] | Fair Value, Inputs, Level 3 [Member] | Debt Securities [Member]
Total pension plan assets
Investment Grade Corporate Bond Funds [Member] | Fair Value Measured at Net Asset Value Per Share [Member] | Debt Securities [Member]
Total pension plan assets
Over 15y Gilts Index Fund [Member] | Debt Securities [Member]
Total pension plan assets	3,684	3,265
Over 15y Gilts Index Fund [Member] | Fair Value, Inputs, Level 1 [Member] | Debt Securities [Member]
Total pension plan assets
Over 15y Gilts Index Fund [Member] | Fair Value, Inputs, Level 2 [Member] | Debt Securities [Member]
Total pension plan assets
Over 15y Gilts Index Fund [Member] | Fair Value, Inputs, Level 3 [Member] | Debt Securities [Member]
Total pension plan assets
Over 15y Gilts Index Fund [Member] | Fair Value Measured at Net Asset Value Per Share [Member] | Debt Securities [Member]
Total pension plan assets	3,684	3,265
Active Corp Bond Over 10 Yr Fund [Member] | Debt Securities [Member]
Total pension plan assets	6,835	5,902
Active Corp Bond Over 10 Yr Fund [Member] | Fair Value, Inputs, Level 1 [Member] | Debt Securities [Member]
Total pension plan assets
Active Corp Bond Over 10 Yr Fund [Member] | Fair Value, Inputs, Level 2 [Member] | Debt Securities [Member]
Total pension plan assets
Active Corp Bond Over 10 Yr Fund [Member] | Fair Value, Inputs, Level 3 [Member] | Debt Securities [Member]
Total pension plan assets
Active Corp Bond Over 10 Yr Fund [Member] | Fair Value Measured at Net Asset Value Per Share [Member] | Debt Securities [Member]
Total pension plan assets	6,835	5,902
Over 5y Index Linked Gilts Fund [Member] | Debt Securities [Member]
Total pension plan assets	12,049	10,724
Over 5y Index Linked Gilts Fund [Member] | Fair Value, Inputs, Level 1 [Member] | Debt Securities [Member]
Total pension plan assets
Over 5y Index Linked Gilts Fund [Member] | Fair Value, Inputs, Level 2 [Member] | Debt Securities [Member]
Total pension plan assets
Over 5y Index Linked Gilts Fund [Member] | Fair Value, Inputs, Level 3 [Member] | Debt Securities [Member]
Total pension plan assets
Over 5y Index Linked Gilts Fund [Member] | Fair Value Measured at Net Asset Value Per Share [Member] | Debt Securities [Member]
Total pension plan assets	12,049	10,724
Philippine Long Govt Securities [Member] | Debt Securities [Member]
Total pension plan assets	1,362	1,133
Philippine Long Govt Securities [Member] | Fair Value, Inputs, Level 1 [Member] | Debt Securities [Member]
Total pension plan assets	1,362	1,133
Philippine Long Govt Securities [Member] | Fair Value, Inputs, Level 2 [Member] | Debt Securities [Member]
Total pension plan assets
Philippine Long Govt Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Debt Securities [Member]
Total pension plan assets
Philippine Long Govt Securities [Member] | Fair Value Measured at Net Asset Value Per Share [Member] | Debt Securities [Member]
Total pension plan assets
Philippine Long Corporate Bonds [Member] | Debt Securities [Member]
Total pension plan assets	723	751
Philippine Long Corporate Bonds [Member] | Fair Value, Inputs, Level 1 [Member] | Debt Securities [Member]
Total pension plan assets	723	751
Philippine Long Corporate Bonds [Member] | Fair Value, Inputs, Level 2 [Member] | Debt Securities [Member]
Total pension plan assets
Philippine Long Corporate Bonds [Member] | Fair Value, Inputs, Level 3 [Member] | Debt Securities [Member]
Total pension plan assets
Philippine Long Corporate Bonds [Member] | Fair Value Measured at Net Asset Value Per Share [Member] | Debt Securities [Member]
Total pension plan assets