Earnings per Common Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Earnings Per Share [Abstract]
Net Income	$ 11,899	$ 8,632	$ 20,801	$ 14,411
Less: Earnings allocated to participating securities	(122)	(82)	(223)	(135)
Earnings allocated to common shareholders, Basic	11,777	8,550	20,578	14,276
Weighted average common shares outstanding	39,260	39,107	39,228	39,073
Basic earnings per common share	$ 0.30	$ 0.22	$ 0.52	$ 0.37
Dilutive effect of equity awards and warrants	48	59	78	86
Earnings allocated to common shareholders, Diluted	$ 11,777	$ 8,550	$ 20,578	$ 14,276
Weighted average diluted common shares outstanding	39,308	39,166	39,306	39,159
Diluted earnings per common share	$ 0.30	$ 0.22	$ 0.52	$ 0.36
Potentially dilutive share options that were not included in the computation of diluted EPS because to do so would be anti-dilutive.	46	62	46	54