Consolidated Statements of Changes in Stockholders' Equity (USD $) In Thousands, except Share data	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	(Accumulated Deficit) Retained Earnings [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Treasury Stock, at Cost [Member]
Beginning Balance at Dec. 31, 2011	$ 868,143	$ 824	$ 955,735	$ (88,416)
Beginning Balance, shares at Dec. 31, 2011		82,418,808
Equity-based compensation	1,191	3	1,188
Equity-based compensation, shares		318,200
Unrealized gain (loss) on derivatives, net of tax	(1,254)				(1,254)
Cash dividends declared to stockholders, net of forfeitures	(500,000)		(500,000)
Net income	74,221			74,221
Ending Balance at Dec. 31, 2012	442,301	827	456,923	(14,195)	(1,254)
Ending Balance, shares at Dec. 31, 2012		82,737,008
Equity-based compensation	6,026	1	6,025
Equity-based compensation, shares		74,561
Unrealized gain (loss) on derivatives, net of tax	1,265				1,265
Issuance of common stock in initial public offering, net of underwriter commissions and offering costs	245,441	100	245,341
Issuance of common stock in initial public offering, net of underwriter commissions and offering costs, shares		10,000,000
Conversion of common stock into unvested restricted shares		(32)	32
Conversion of common stock into unvested restricted shares, shares		(3,216,719)
Vesting of restricted shares		3	(3)
Vesting of restricted shares, shares		334,066
Shares withheld for tax withholdings	(852)		(852)
Shares withheld for tax withholdings, shares		(28,463)
Cash dividends declared to stockholders, net of forfeitures	(53,911)		(18,072)	(35,839)
Repurchase of shares of treasury stock, at cost	(44,163)					(44,163)
Net income	51,920			51,920
Ending Balance at Dec. 31, 2013	648,027	899	689,394	1,886	11	(44,163)
Ending Balance, shares at Dec. 31, 2013	89,900,453	89,900,453
Equity-based compensation	2,349		2,349
Unrealized gain (loss) on derivatives, net of tax	(494)				(494)
Vesting of restricted shares		3	(3)
Vesting of restricted shares, shares		299,583
Shares withheld for tax withholdings	(213)		(213)
Shares withheld for tax withholdings, shares		(8,936)
Cash dividends declared to stockholders, net of forfeitures	(54,345)		(36,056)	(18,289)
Repurchase of shares of treasury stock, at cost	(65,708)					(65,708)
Net income	49,919			49,919
Ending Balance at Dec. 31, 2014	$ 579,535	$ 902	$ 655,471	$ 33,516	$ (483)	$ (109,871)
Ending Balance, shares at Dec. 31, 2014	90,191,100	90,191,100