Acquired Loans - Changes in Accretable Yield of Acquired Loans (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
Change in accretable difference on acquired loans [Abstract]
Accretable yield at beginning of period		$ (52,672)	$ (77,149)
Accretion to interest income		18,405	30,501
Disposals		6,488	10,013
Reclassification from nonaccretable difference	[1]	(11,139)	(16,037)
Accretable yield at end of period		$ (38,918)	$ (52,672)

[1] Reclassifications from nonaccretable difference are due to lower loss expectations and improvements in expected cash flows.