Accumulated Other Comprehensive Income (Loss) and Shareholders' Equity (Narrative) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 30, 2017	Mar. 31, 2016
Class of Stock [Line Items]
Accumulated other comprehensive income (loss)	$ (3,477)	$ (3,611)
Common Stock
Class of Stock [Line Items]
Stock repurchase program, remaining authorized repurchase amount	70,000
Interest rate swap
Class of Stock [Line Items]
Derivative, notional amount			$ 150,000
Derivative, fixed interest rate			1.29%
Derivative liability	5,100
Accumulated other comprehensive income (loss)	$ 3,500