Consolidated Statements of Changes in Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Common Stock Common Class A	Common Stock Common Class B	Additional Paid In Capital	Treasury Stock Common Class A	Retained Earnings	Accumulated Comprehensive Income (Loss)	Total
Balance at the beginning of the period at Dec. 31, 2013	$ 1	$ 3	$ 240,817	$ (938)	$ 1,541	$ (636)	$ 240,788
Balance at the beginning of the period (in shares) at Dec. 31, 2013	11,241	33,000
Consolidated Statements of Changes in Stockholders' Equity
Net income					10,557		10,557
Issuance of restricted stock			2,908				2,908
Issuance of restricted stock (in shares)	305
Excess tax benefits related to the issuance of restricted stock			120				120
Stock-based compensation			3,012				3,012
Repurchases of shares				(1,023)			(1,023)
Exercise of warrants			1				1
Conversion of Class B common stock to Class A common stock (in shares)	2,973	(2,973)
Other comprehensive income, net of tax						50	50
Balance at the end of the period at Dec. 31, 2014	$ 1	$ 3	246,858	(1,961)	12,098	(586)	256,413
Balance at the end of the period (in shares) at Dec. 31, 2014	14,519	30,027
Consolidated Statements of Changes in Stockholders' Equity
Net income					13,739		13,739
Issuance of restricted stock			2,522				2,522
Issuance of restricted stock (in shares)	324
Excess tax benefits related to the issuance of restricted stock			272				272
Stock-based compensation			3,053				3,053
Repurchases of shares				(1,183)			(1,183)
Issuance of Class A common stock			5,407				5,407
Issuance of Class A common stock (in shares)	479
Repurchase of warrants			(1,778)				(1,778)
Exercise of warrants			60				60
Exercise of warrants (in shares)	5
Exercise of stock options			157				$ 157
Exercise of stock options (in shares)	15						15
Other comprehensive income, net of tax						(21)	$ (21)
Balance at the end of the period at Dec. 31, 2015	$ 1	$ 3	256,551	(3,144)	25,837	(607)	278,641
Balance at the end of the period (in shares) at Dec. 31, 2015	15,342	30,027
Consolidated Statements of Changes in Stockholders' Equity
Net income					18,000		18,000
Issuance of restricted stock			934				934
Issuance of restricted stock (in shares)	328
Excess tax benefits related to the issuance of restricted stock			210				210
Stock-based compensation			3,757				3,757
Repurchases of shares				(31,925)			(31,925)
Repurchase of warrants			(976)				(976)
Exercise of warrants			420				420
Exercise of warrants (in shares)	35
Conversion of Class B common stock to Class A common stock	$ 1	$ (1)
Conversion of Class B common stock to Class A common stock (in shares)	9,226	(9,226)
Exercise of stock options			155				155
Exercise of stock options (in shares)	13
Other comprehensive income, net of tax						124	124
Balance at the end of the period at Dec. 31, 2016	$ 2	$ 2	$ 261,051	$ (35,069)	$ 43,837	$ (483)	$ 269,340
Balance at the end of the period (in shares) at Dec. 31, 2016	24,944	20,801