Loans - Outstanding Principal and Carrying Amount of Acquired Loans (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Outstanding principal balance and the carrying amount of loan acquired [Abstract]
Accretion income included in interest income	$ 2,379
Interest income, including accretion, on loans	11,333
Outstanding principal balance	162,190	$ 84,892
Carrying amount	151,026	78,111
Outstanding principal balance and the carrying amount of loan acquired, impaired [Abstract]
Outstanding principal balance	43,325	18,357
Carrying amount	$ 35,569	$ 14,933