Condensed Consolidated Statements Of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Statement [Abstract]
Revenues	$ 267,907	$ 279,140
Cost of sales	134,323	149,774
Gross profit	133,584	129,366
Selling, general and administrative expenses	118,002	115,123
Income from operations	15,582	14,243
Foreign currency gain (loss), net	276	(1,247)
Interest income	150	216
Interest expense	(184)	(243)
Other income	124	82
Income before income taxes	15,948	13,051
Income tax expense	(4,938)	(2,905)
Net income	11,010	10,146
Dividends on Series A convertible preferred stock	(3,000)	(3,000)
Dividend equivalents on Series A convertible preferred shares related to redemption value accretion and beneficial conversion feature	(855)	(785)
Net income attributable to common stockholders	$ 7,155	$ 6,361
Net income per common share:
Basic (in dollars per share)	$ 0.08	$ 0.07
Diluted (in dollars per share)	$ 0.08	$ 0.07