Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Revenues	$ 862,459	$ 955,097	$ 859,634
Cost of sales	402,159	430,382	390,524
Gross profit	460,300	524,715	469,110
Selling and administrative expense	373,817	400,141	355,617
Research and development expense	40,473	45,460	42,188
Total operating expenses	414,290	445,601	397,805
Income from operations	46,010	79,114	71,305
Interest expense	44,052	42,701	20,652
Other expense	355	5,188	0
Income before income taxes	1,603	31,225	50,653
Provision (benefit) for income taxes	(7,914)	2,605	9,799
Net income	$ 9,517	$ 28,620	$ 40,854
Earnings per share:
Basic (in dollars per share)	$ 0.33	$ 1.01	$ 1.45
Diluted (in dollars per share)	$ 0.32	$ 0.97	$ 1.41
Other comprehensive income (loss), before income tax:
Foreign currency translation adjustments	$ 6,963	$ 25	$ (8,369)
Pension liability	(6,499)	35	(885)
Cash flow hedging	(8,489)	(4,736)	10,985
Other comprehensive income (loss), before income tax	(8,025)	(4,676)	1,731
Provision (benefit) for income taxes related to items in other comprehensive income	(3,621)	(1,136)	2,441
Other Comprehensive Income (Loss), Net of Income Tax	(4,404)	(3,540)	(710)
Comprehensive income	$ 5,113	$ 25,080	$ 40,144