Acquisitions and Divestitures - Proforma Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Business Combinations [Abstract]
Total revenue (net interest income plus other income)	$ 263,070	$ 253,668
Net income	61,572	39,979
Net income available to common shareholders	$ 61,572	$ 37,599
Earnings per share:
Basic (in dollars per share)	$ 1.63	$ 0.98
Diluted (in dollars per share)	$ 1.61	$ 0.97