Consolidated Statements of Stockholders' Equity (USD $) In Thousands		Total	Common Stock		Paid-in Capital	Retained Earnings
Balance at Dec. 31, 2012		$ 138,136	$ 147	[1]	$ 0	$ 137,989	[1]
Balance (in shares) at Dec. 31, 2012	[1]		36,777
Net income	[2]	29,781
Stock options exercised and restricted stock awards vested, including tax benefits		1,488	1	[1]	1,487
Stock options exercised and restricted stock awards vested, including tax benefits (in shares)	[1]		171
Share-based compensation		1,054			1,054
Stock repurchased and retired		(4,817)	(1)	[1]	(2,541)	(2,275)	[1]
Stock repurchased and retired (in shares)	[1]		(238)
Dividends	[2]	(3,712)				(3,712)	[1]
Balance at Sep. 30, 2013		$ 161,930	$ 147	[1]	$ 0	$ 161,783	[1]
Balance (in shares) at Sep. 30, 2013	[1]		36,710

[1] Reflects three-for-two stock split effective July 2, 2013

[2] Includes cash payment of fractional shares from three-for-two stock split effective July 2, 2013