Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning balance (shares) at Dec. 31, 2017		68,791	25,987
Beginning balance at Dec. 31, 2017	$ 185,865	$ 95	$ (334,312)	$ 373,045	$ 190,431	$ (43,394)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation	2,394			2,394
Exercises of stock options, issuance of restricted stock awards, and vests of restricted stock units (shares)		885	60
Exercises of stock options, issuance of restricted stock awards, and vests of restricted stock units	(692)	$ 1	$ (836)	143
Repurchases of common stock (shares)		1,399	1,399
Repurchases of common stock	(20,061)		$ (20,061)
Series A Convertible Preferred dividends	(3,000)				(3,000)
Series A Convertible Preferred accretion	(931)				(931)
Net income	16,454				16,454
Other comprehensive loss	2,229					2,229
Other	1,226			1,226
Ending balance (shares) at Mar. 31, 2018		68,277	27,446
Ending balance at Mar. 31, 2018	183,484	$ 96	$ (355,209)	376,808	202,954	(41,165)
Beginning balance (shares) at Dec. 31, 2018		73,306	29,656
Beginning balance at Dec. 31, 2018	150,308	$ 103	$ (397,491)	481,133	121,215	(54,652)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation	3,634			3,634
Exercises of stock options, issuance of restricted stock awards, and vests of restricted stock units (shares)		836	49
Exercises of stock options, issuance of restricted stock awards, and vests of restricted stock units	(1,061)	$ 1	$ (1,227)	165
Repurchases of common stock (shares)		2,133	2,133
Repurchases of common stock	(53,478)		$ (53,478)
Net income	24,710				24,710
Other comprehensive loss	(941)					(941)
Ending balance (shares) at Mar. 31, 2019		72,009	31,838
Ending balance at Mar. 31, 2019	$ 122,945	$ 104	$ (452,196)	$ 484,932	$ 145,698	$ (55,593)