Loans - Acquired Loans (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Credit impaired acquired loans:
Outstanding principal balance	$ 56,985		$ 60,554
Recorded investment	42,652		46,174
Recorded investment	42,652		46,174
Discount, net	14,333		14,380
Other acquired loans:
Outstanding principal balance	1,058,575		1,162,068
Recorded investment	1,049,983		1,150,938
Discount, net	8,538		10,968
Total acquired loans:
Outstanding principal balance	1,115,560		1,222,622
Deferred fees, net	(54)		(162)
Recorded investment	1,092,635		1,197,112
Discount, net	22,871		$ 25,348
Changes in the accretable yield for credit impaired acquired loans
Beginning balance	966	$ 685
Additions	0	0
Reclassifications from nonaccretable yield	0	480
Accretion	0	(63)
Balance at period end	$ 966	$ 1,102