Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	0 Months Ended		3 Months Ended				6 Months Ended				0 Months Ended
	Jun. 05, 2014	May 21, 2013	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013		Jul. 16, 2014 Subsequent Event [Member]
Earnings Per Share [Abstract]
Net income			$ 11,363		$ 12,119		$ 21,185		$ 19,259
Basic weighted average shares (in shares)			55,004,175	[1]	55,139,577	[1]	55,036,281	[1]	55,140,260	[1]
Effect of dilutive stock options and restricted stock (in shares)			564,037	[1]	585,816	[1]	567,698	[1]	444,042	[1]
Diluted weighted average shares (in shares)			55,568,212	[1]	55,725,393	[1]	55,603,979	[1]	55,584,302	[1]
Basic (usd per share)			$ 0.21	[1]	$ 0.22	[1]	$ 0.38	[1]	$ 0.35	[1]
Diluted (usd per share)			$ 0.20	[1]	$ 0.22	[1]	$ 0.38	[1]	$ 0.35	[1]
Anti-dilutive shares (in shares)			18,445	[1]	11,250	[1]	19,448	[1]	11,250	[1]
Subsequent Event [Line Items]
Stock split, conversion ratio	1.5	1.5									1.5

[1] Reflects three-for-two stock split effective July 16, 2014