Consolidated Statements Of Operations - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2019		Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Revenues		$ 1,230,593		$ 1,088,205	$ 1,023,513
Cost of sales		613,537		528,051	506,292
Gross profit		617,056		560,154	517,221
Selling, general and administrative expenses		488,407		495,028	494,601
Asset impairments		0		2,182	5,284
Income from operations		128,649		62,944	17,336
Foreign currency gains (losses), net		(1,323)		1,318	563
Interest income		601		1,281	870
Interest expense		(8,636)		(955)	(869)
Other income, net		31		569	280
Income before income taxes		119,322		65,157	18,180
Income tax expense (benefit)		(175)		14,720	7,942
Net income		119,497		50,437	10,238
Dividends on Series A convertible preferred stock	[1]	0		(108,224)	(12,000)
Dividend equivalents on Series A convertible preferred shares related to redemption value accretion and beneficial conversion feature		0	[1]	(11,429)	(3,532)
Net income (loss) attributable to common stockholders		$ 119,497		$ (69,216)	$ (5,294)
Net income (loss) per common share:
Basic (in dollars per share)		$ 1.70		$ (1.01)	$ (0.07)
Diluted (in dollars per share)		$ 1.66		$ (1.01)	$ (0.07)
Weighted average common shares outstanding:
Basic (shares)		70,357		68,421	72,255
Diluted (shares)		71,771		68,421	72,255

[1] On December 5, 2018, all issued and outstanding shares of Series A Convertible Preferred Stock were repurchased in exchange for cash or converted to common stock. As a result, amounts reported for the year ended December 31, 2018, include amounts resulting from the repurchase and conversion, in addition to dividends, payments to induce conversion, and accretion of dividend equivalents prior to December 5, 2018.