Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income/(Loss)
Beginning balance (in shares) at Dec. 31, 2016		129,202,979
Beginning balance at Dec. 31, 2016	$ 1,114,219	$ 1,292	$ 771,346	$ 376,202	$ (34,621)
Increase (Decrease) in Stockholders' Equity
Net income	52,411			52,411
Other comprehensive income (loss), net of tax	18,112				18,112
Issuance of common stock under employee plans, including tax benefits (in shares)		1,775,968
Issuance of common stock under employee plans, including tax benefits	29,094	$ 18	29,076
Stock-based compensation	29,557		29,557
Dividends paid	(109,551)			(109,551)
Ending balance (in shares) at Dec. 31, 2017		130,978,947
Ending balance at Dec. 31, 2017	1,128,021	$ 1,310	829,979	313,241	(16,509)
Increase (Decrease) in Stockholders' Equity
Net income	155,057			155,057
Other comprehensive income (loss), net of tax	(422)				(422)
Issuance of common stock under employee plans, including tax benefits (in shares)		1,676,994
Issuance of common stock under employee plans, including tax benefits	30,694	$ 17	30,677
Stock-based compensation	36,888		36,888
Dividends paid	$ (121,537)			(121,537)
Ending balance (in shares) at Dec. 31, 2018	132,655,941	132,655,941
Ending balance at Dec. 31, 2018	$ 1,238,358	$ 1,327	897,544	356,418	(16,931)
Increase (Decrease) in Stockholders' Equity
Net income	162,151			162,151
Other comprehensive income (loss), net of tax	(4,139)				(4,139)
Issuance of common stock under employee plans, including tax benefits (in shares)		1,848,594
Issuance of common stock under employee plans, including tax benefits	32,354	$ 18	32,336
Stock-based compensation	50,797		50,797
Repurchase of common stock (in shares)		(4,000,000)
Repurchase of common stock	(171,316)	$ (40)	(27,099)	(144,177)
Dividends paid	$ (131,855)			(131,855)
Ending balance (in shares) at Dec. 31, 2019	130,504,535	130,504,535
Ending balance at Dec. 31, 2019	$ 1,176,350	$ 1,305	$ 953,578	$ 242,537	$ (21,070)