Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Reconciliation of the component parts of earnings per share [Abstract]
Net income	$ 9,066	$ 7,766	$ 17,975	$ 15,148
Less: Net income allocated to participating securities	10		20
Net income allocated to common shareholders	9,056	7,766	17,955	15,148
Basic EPS [Abstract]
Distributed earnings allocated to common stock	6,139		12,287
Undistributed earnings allocated to common stock	2,917		5,668
Net income allocated to common shareholders	9,056	7,766	17,955	15,148
Weighted average common shares outstanding including participating securities basic (in shares)	93,667,000		93,609,000
Less: Participating securities (in shares)	106,000		106,000
Weighted average common shares (in shares)	93,561,000	77,363,000	93,503,000	77,302,000
Basic EPS (in dollars per share)	$ 0.097	$ 0.100	$ 0.192	$ 0.196
Diluted EPS [Abstract]
Net income allocated to common shareholders	9,056	7,766	17,955	15,148
Weighted average common shares for basic EPS (in shares)	93,561,000	77,363,000	93,503,000	77,302,000
Effect of Dilutive Securities [Abstract]
Stock Options - Income		$ 0		$ 0
Stock Options - Weighted Average Shares Outstanding (in shares)	1,000	0	1,000	0
Stock Options - Per Share Amounts (in dollars per share)		$ 0		$ 0
Weighted average common shares including potential dilutive shares (in shares)	93,562,000	77,363,000	93,504,000	77,302,000
Diluted EPS	$ 0.097	$ 0.100	$ 0.192	$ 0.196
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average number of antidilutive stock options excluded from diluted earnings per share (in shares)	3,100,000	2,600,000	3,100,000	2,800,000