Loans - Acquired Loans (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Credit impaired acquired loans:
Outstanding principal balance	$ 42,265		$ 60,554
Recorded investment	34,122		46,174
Discount, net	8,143		14,380
Other acquired loans:
Outstanding principal balance	867,193		1,162,068
Recorded investment	861,437		1,150,938
Discount, net	5,555		10,968
Total acquired loans:
Outstanding principal balance	909,458		1,222,622
Deferred fees, net	(201)		(162)
Recorded investment	895,559		1,197,112
Discount, net	13,698		$ 25,348
Changes in the accretable yield for credit impaired acquired loans
Beginning balance	967	$ 685
Reclassifications from nonaccretable yield	3,087	557
Accretion	(1,051)	(196)
Balance at period end	$ 3,003	$ 1,046