CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Earnings	Accumulated Earnings Cumulative Effect, Period of Adoption, Adjustment
Beginning balance (in shares) at Dec. 31, 2017			56,501
Beginning balance at Dec. 31, 2017	$ 1,188,202	$ (1,564)	$ 565	$ 686,962	$ (172,407)	$ 673,082	$ (1,564)
Increase (Decrease) in Stockholders' Equity
Net income	65,636					65,636
Other comprehensive income (loss)	(50,964)				(50,964)
Stock-based compensation	16,792			16,792
Issuance of common stock for restricted share vesting, net of employee tax withholding (in shares)			160
Issuance of common stock for restricted share vesting, net of employee tax withholdings	$ (3,266)		$ 1	(3,267)
Repurchases of common stock (in shares)	(800)		(814)
Repurchases of common stock	$ (45,080)		$ (8)	(45,072)
Ending balance (in shares) at Dec. 31, 2018			55,847
Ending balance at Dec. 31, 2018	1,169,756		$ 558	655,415	(223,371)	737,154
Increase (Decrease) in Stockholders' Equity
Net income	97,740					97,740
Other comprehensive income (loss)	13,320				13,320
Stock-based compensation	17,816			17,816
Issuance of common stock for restricted share vesting, net of employee tax withholding (in shares)			249
Issuance of common stock for restricted share vesting, net of employee tax withholdings	$ (7,429)		$ 3	(7,432)
Repurchases of common stock (in shares)	(300)		(298)
Repurchases of common stock	$ (21,390)		$ (3)	(21,387)
Ending balance (in shares) at Dec. 31, 2019			55,798
Ending balance at Dec. 31, 2019	1,269,813		$ 558	644,412	(210,051)	834,894
Increase (Decrease) in Stockholders' Equity
Net income	134,837					134,837
Other comprehensive income (loss)	(1,426)				(1,426)
Stock-based compensation	18,502			18,502
Issuance of common stock for restricted share vesting, net of employee tax withholding (in shares)			179
Issuance of common stock for restricted share vesting, net of employee tax withholdings	$ (5,331)		$ 2	(5,333)
Repurchases of common stock (in shares)	(1,200)		(1,204)
Repurchases of common stock	$ (74,844)		$ (12)	(74,832)
Ending balance (in shares) at Dec. 31, 2020			54,773
Ending balance at Dec. 31, 2020	$ 1,341,551		$ 548	$ 582,749	$ (211,477)	$ 969,731