CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common stock	Additional paid-in capital	Treasury stock	Retained earnings	Retained earnings Cumulative Effect, Period of Adoption, Adjustment	Accumulated other comprehensive income (loss)
Beginning balance (in shares) at Dec. 31, 2017			47,854,510		0
Beginning balance at Dec. 31, 2017	$ 1,020,305	$ 1,599	$ 479	$ 325,854	$ 0	$ 723,062	$ 1,599	$ (29,090)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	128,687					128,687
Other comprehensive income, net of tax	(16,889)							(16,889)
Dividends	$ (82,573)					(82,573)
Exercise of stock options (in shares)	67,898		67,898
Exercise of stock options	$ 1,540		$ 1	1,539
Issuance of shares under Employee Stock Purchase Plan (in shares)			33,262
Issuance of shares under Employee Stock Purchase Plan	2,084			2,084
Vested restricted stock (in shares)			169,512
Vested restricted stock	0		$ 2	(2)
Repurchase and retirement of common stock (in shares)			(52,912)		(600,000)
Repurchase and retirement of common stock	(47,102)		$ (1)	(3,230)	$ (42,543)	(1,328)
Exchange of Series B preferred stock (in shares)			10,530
Exchange of Series B preferred stock	0
Share based compensation	28,093			27,965		128
Ending balance at Dec. 31, 2018	1,035,744		$ 481	354,210	$ (42,543)	769,575		(45,979)
Ending balance (in shares) at Dec. 31, 2018			48,082,800		(600,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	218,806					218,806
Other comprehensive income, net of tax	(483)							(483)
Dividends	$ (43,918)					(43,918)
Exercise of stock options (in shares)	189,436		189,436
Exercise of stock options	$ 5,274		$ 2	5,272
Issuance of shares under Employee Stock Purchase Plan (in shares)			66,413
Issuance of shares under Employee Stock Purchase Plan	4,512		$ 1	4,511
Equity portion of convertible debt	88,138			88,138
Vested restricted stock (in shares)			185,227
Vested restricted stock	0		$ 1	(1)
Repurchase and retirement of common stock (in shares)			(868,947)		600,000
Repurchase and retirement of common stock	(20,803)		$ (9)	(10,334)	$ 42,543	(53,003)
Share based compensation	23,922			23,856		66
Ending balance at Dec. 31, 2019	1,311,192		$ 476	465,652	$ 0	891,526		(46,462)
Ending balance (in shares) at Dec. 31, 2019			47,654,929		0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	150,668					150,668
Other comprehensive income, net of tax	$ (8,344)							(8,344)
Exercise of stock options (in shares)	42,740		42,740
Exercise of stock options	$ 1,619			1,619
Issuance of shares under Employee Stock Purchase Plan (in shares)			118,629
Issuance of shares under Employee Stock Purchase Plan	7,382		$ 1	7,381
Exercise of 3.25% Convertible Note	(12)			(12)
Vested restricted stock (in shares)			273,201
Vested restricted stock	0		$ 3	(3)
Repurchase and retirement of common stock (in shares)			(3,742,869)
Repurchase and retirement of common stock	(275,654)		$ (37)	(42,530)		(233,087)
Share based compensation	24,006			24,006
Other, net	161			161
Ending balance at Dec. 31, 2020	$ 1,211,018		$ 443	$ 456,274	$ 0	$ 809,107		$ (54,806)
Ending balance (in shares) at Dec. 31, 2020			44,346,630		0