Consolidated Statement of Changes in Shareholders' Equity - 6 months ended Jul. 01, 2017 - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Treasury Stock at Cost	Accumulated Other Comprehensive (Loss) Income
Beginning Balance (in shares) at Dec. 31, 2016		67,585,675			25,747,541
Beginning Balance at Dec. 31, 2016	$ 542,557	$ 676	$ 199,414	$ 1,512,993	$ (1,167,437)	$ (3,089)
Net income	69,893			69,893
Dividends ($0.18 per share)	(7,544)			(7,544)
Issuance of stock related to stock-based compensation plans (in shares)		110,812			1,952
Issuance of stock related to stock-based compensation plans	1,597	$ 1	1,759		$ (163)
Stock-based compensation	2,237		2,237
Other comprehensive income	750					750
Ending Balance (in shares) at Jul. 01, 2017		67,696,487			25,749,493
Ending Balance at Jul. 01, 2017	$ 609,490	$ 677	$ 203,410	$ 1,575,342	$ (1,167,600)	$ (2,339)