Net Income Per Common Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Basic
Net income applicable to common stock	$ 13,597	$ 7,571
Average common shares outstanding (shares)	31,436,148	25,186,229
Net income per common share - basic (usd per share)	$ 0.43	$ 0.30
Diluted
Net income applicable to common stock	$ 13,597	$ 7,571
Average common shares outstanding (shares)	31,436,148	25,186,229
Effect of dilutive stock-based compensation (shares)	232,214	102,556
Average common shares outstanding - diluted	31,668,362	25,288,785
Net income per common share - diluted (usd per share)	$ 0.43	$ 0.30