Purchase Credit Impaired ("PCI") Loans - Rollforward of PCI Loans, Net of Allowance for Loan Losses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Balance at beginning of period	$ 83,693	$ 125,100
Principal reductions and interest payments	(24,441)	(35,718)
Accretion of loan discount	10,775	15,747
Changes in contractual and expected cash flows due to remeasurement	14,707	8,467
Reductions due to disposals	(20,151)	(29,903)
Balance at end of period	64,583	83,693
Contractual Cashflows
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Balance at beginning of period	178,145	266,068
Principal reductions and interest payments	(24,441)	(35,718)
Accretion of loan discount	0	0
Changes in contractual and expected cash flows due to remeasurement	(3,574)	(2,170)
Reductions due to disposals	(33,441)	(50,035)
Balance at end of period	116,689	178,145
Non-accretable Difference
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Balance at beginning of period	65,719	87,438
Principal reductions and interest payments	0	0
Accretion of loan discount	0	0
Changes in contractual and expected cash flows due to remeasurement	(30,413)	(7,403)
Reductions due to disposals	(8,541)	(14,316)
Balance at end of period	26,765	65,719
Accretable Yield
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Balance at beginning of period	28,733	53,530
Principal reductions and interest payments	0	0
Accretion of loan discount	10,775	15,747
Changes in contractual and expected cash flows due to remeasurement	12,132	(3,234)
Reductions due to disposals	(4,749)	(5,816)
Balance at end of period	$ 25,341	$ 28,733