Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2017	Dec. 31, 2016	Dec. 26, 2015
Statement of Comprehensive Income [Abstract]
Foreign currency translation, deferred tax effect	$ 621	$ (638)	$ 524
Unrealized gains (losses) on interest rate swaps, deferred tax effect	(778)	(882)	(867)
Unrealized loss on pension plan, deferred tax effect	$ 0	$ 0	$ 866