Acquired Loans - Changes in Accretable Yield of Acquired Loans (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014
Change in accretable difference on acquired loans [Abstract]
Accretable yield at beginning of period		$ (77,149)	$ (109,006)
Accretion to interest income		30,501	48,627
Disposals		10,013	16,383
Reclassification from nonaccretable difference	[1]	(16,037)	(33,153)
Accretable yield at end of period		$ (52,672)	$ (77,149)

[1] (1) Reclassifications from nonaccretable difference are due to lower loss expectations and improvements in expected cashflows.