Consolidated Statements of Changes In Stockholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Noncontrolling Interest [Member]	Total
Balances (in shares) at Dec. 31, 2016	112,896,377
Balances at Dec. 31, 2016	$ 1,129	$ 953,440	$ (23,824)	$ (615)	$ 50	$ 930,180
Cumulative effect of change in accounting principle	0	0	15,777	0	0	15,777
Net income	0	0	189,390	0	0	189,390
Comprehensive income (loss), net of tax	$ 0	0	0	433	0	$ 433
Stock options exercised (in shares)	241,964					241,964
Stock options exercised	$ 2	2,082	0	0	0	$ 2,084
Release of restricted stock units, net of tax (in shares)	520,854
Release of restricted stock units, net of tax	$ 5	(8,009)	0	0	0	(8,004)
Release of performance stock units, net of tax (in shares)	173,653
Release of performance stock units, net of tax	$ 2	(1,793)	0	0	0	$ (1,791)
Shares repurchased and retired (in shares)	(1,198,430)					(1,198,000)	[1],[2]
Shares repurchased and retired	$ (12)	(31,915)	0	0	0	$ (31,927)	[2]
Dividends declared	0	0	(16,918)	0	0	(16,918)
Share-based compensation costs	0	17,413	0	0	0	17,413
Other	$ 0	640	0	0	(50)	590
Balances (in shares) at Dec. 31, 2017	112,634,418
Balances at Dec. 31, 2017	$ 1,126	931,858	164,425	(182)	0	1,097,227
Cumulative effect of change in accounting principle	0	0	(312)	312	0	0
Net income	0	0	115,048	0	0	115,048
Comprehensive income (loss), net of tax	$ 0	0	0	(1,195)	0	$ (1,195)
Stock options exercised (in shares)	338,426					338,426
Stock options exercised	$ 3	3,539	0	0	0	$ 3,542
Release of restricted stock units, net of tax (in shares)	300,177
Release of restricted stock units, net of tax	$ 3	(3,619)	0	0	0	(3,616)
Release of performance stock units, net of tax (in shares)	337,537
Release of performance stock units, net of tax	$ 4	(5,274)	0	0	0	$ (5,270)
Shares repurchased and retired (in shares)	(1,853,453)					(1,853,000)	[1],[2]
Shares repurchased and retired	$ (18)	(59,552)	0	0	0	$ (59,570)	[2]
Dividends declared	0	0	(25,804)	0	0	(25,804)
Share-based compensation costs	$ 0	25,379	0	0	0	$ 25,379
Balances (in shares) at Dec. 31, 2018	111,757,105					111,757,105
Balances at Dec. 31, 2018	$ 1,118	892,331	253,357	(1,065)	0	$ 1,145,741
Net income	0	0	157,636	0	0	157,636
Comprehensive income (loss), net of tax	$ 0	0	0	535	0	$ 535
Stock options exercised (in shares)	242,357					242,357
Stock options exercised	$ 2	2,375	0	0	0	$ 2,377
Release of restricted stock units, net of tax (in shares)	358,361
Release of restricted stock units, net of tax	$ 4	(4,391)	0	0	0	(4,387)
Release of performance stock units, net of tax (in shares)	270,960
Release of performance stock units, net of tax	$ 3	(3,769)	0	0	0	$ (3,766)
Shares repurchased and retired (in shares)	(1,086,675)					(1,087,000)	[1],[2]
Shares repurchased and retired	$ (12)	(28,033)	0	0	0	$ (28,045)	[2]
Dividends declared	0	0	(30,051)	0	0	(30,051)
Share-based compensation costs	$ 0	25,202	0	0	0	$ 25,202
Balances (in shares) at Dec. 31, 2019	111,542,108					111,542,108
Balances at Dec. 31, 2019	$ 1,115	$ 883,715	$ 380,942	$ (530)	$ 0	$ 1,265,242

[1] All shares repurchased have been retired and constitute authorized but unissued shares.

[2] Shares repurchased reflect repurchases settled during the twelve months ended December 31, 2019, 2018 and 2017. These amounts exclude repurchases, if any, traded but not yet settled on or before December 31, 2019, 2018 and 2017.