Net Income Per Common Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Net Income	$ 19,603	$ 16,476
Preferred Stock Dividends	(1,222)	0
Net income to common shareholders	18,381	16,476
Effect of dilutive stock options, income		0
Diluted net income	$ 18,381	$ 16,476
Weighted Average Common Shares	54,300,020	49,480,426
Effect of dilutive stock options, number of shares	754	469
Diluted, Weighted Average Number Common Shares	54,300,774	49,480,895
Basic Net Income Per Common Share	$ 0.34	$ 0.33
Diluted Net Income Per Common Share	$ 0.34	$ 0.33
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		15,000