Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock Outstanding [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Treasury Stock [Member]	Total
Balance (in shares) at Dec. 31, 2016	5,708,223
Balance at Dec. 31, 2016	$ 59	$ 17,669	$ 530,431	$ (446)	$ (74,547)	$ 473,166
Net income			235,171			235,171
Changes in pension, net of tax				94		94
Equity-based compensation		10,743				10,743
Issuance of equity awards, net of forfeitures (in shares)	31,129
Repurchases of common stock (in shares)	(900)
Repurchases of common stock					(528)	$ (528)
Withholding tax for equity awards (in shares)	(7,010)					(7,010)
Withholding tax for equity awards					(4,983)	$ (4,983)
Dividends paid to stockholders			(37,216)			(37,216)
Changes in pension, net of tax				94		94
Deferred gain (loss) on cash flow hedges and other, net of tax						94
Balance (in shares) at Dec. 31, 2017	5,731,442
Balance at Dec. 31, 2017	$ 59	28,412	728,386	(352)	(80,058)	676,447
Net income			164,760			164,760
Changes in pension, net of tax				256	0
Equity-based compensation		10,486				10,486
Issuance of equity awards, net of forfeitures (in shares)	20,800
Repurchases of common stock (in shares)	(38,814)
Repurchases of common stock					(26,582)	$ (26,582)
Withholding tax for equity awards (in shares)	(10,026)					(10,026)
Withholding tax for equity awards					(7,155)	$ (7,155)
Dividends paid to stockholders			(42,854)			(42,854)
Changes in pension, net of tax				256	0
Deferred gain (loss) on cash flow hedges and other, net of tax						256
Balance (in shares) at Dec. 31, 2018	5,703,402
Balance at Dec. 31, 2018	$ 59	38,898	850,292	(96)	(113,795)	775,358
Net income			178,582			178,582
Equity-based compensation		12,300				12,300
Issuance of equity awards, net of forfeitures (in shares)	21,480
Repurchases of common stock (in shares)	(5,984)
Repurchases of common stock					(5,073)	$ (5,073)
Withholding tax for equity awards (in shares)	(3,521)					(3,521)
Withholding tax for equity awards					(3,017)	$ (3,017)
Dividends paid to stockholders			(48,527)			(48,527)
Lease accounting standard adoption cumulative adjustment at Dec. 31, 2018			8			8
Deferred gain (loss) on cash flow hedges and other, net of tax				(68,062)		(68,062)
Balance (in shares) at Dec. 31, 2019	5,715,377
Balance at Dec. 31, 2019	$ 59	$ 51,198	$ 980,355	$ (68,158)	$ (121,885)	$ 841,569