Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 29, 2018	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017
Income Statement [Abstract]
Net sales	$ 468,129	$ 449,006	$ 931,456	$ 884,947
Cost of sales	332,486	314,513	661,706	626,108
Gross profit	135,643	134,493	269,750	258,839
Selling, general and administrative expenses	114,339	107,952	226,092	218,829
Restructuring costs	1,954	0	3,647	0
Net (gain) loss on sale of assets	(1,525)	15	(1,588)	(5)
Operating income	20,875	26,526	41,599	40,015
Interest expense, net	5,002	6,122	10,354	10,282
Non-service pension and post retirement benefit cost (income)	(3,039)	(866)	(6,068)	(1,585)
Other expense (income), net	361	(69)	19	(228)
Earnings before income taxes	18,551	21,339	37,294	31,546
Income tax expense	3,457	7,881	8,134	11,797
Net earnings	$ 15,094	$ 13,458	$ 29,160	$ 19,749
Earnings per share:
Basic earnings per share (in usd per share)	$ 0.54	$ 0.49	$ 1.04	$ 0.72
Diluted earnings per share (in usd per share)	$ 0.53	$ 0.48	$ 1.03	$ 0.70
Average shares outstanding:
Basic (in shares)	27,971	27,557	27,911	27,351
Diluted (in shares)	28,349	27,842	28,258	28,370
Dividends declared per share (in usd per share)	$ 0.20	$ 0.20	$ 0.40	$ 0.40