Loans and Leases (Details 8) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, beginning of period	$ 132,139			$ 139,456
Reserve for Unfunded Loan Commitments, Balance, beginning of period	35,361		$ 20,263	28,635	$ 17,523
Allowance for Credit Losses, Balance, beginning of period	167,500		166,221	168,091	174,761
Allowance for Loan and Lease Losses, Charge-offs	(3,308)			(33,696)
Reserve for Unfunded Loan Commitments, Charge-offs	0		0	0	0
Allowance for Credit Losses, Charge-offs	(3,308)		(6,007)	(33,696)	(55,575)
Allowance for Loan and Lease Loss, Recoveries	1,589			9,886
Reserve for Unfunded Loan Commitments, Recoveries	0		0	0	0
Allowance for Credit Losses, Recoveries	1,589		5,082	9,886	9,883
Allowance for Loan and Lease Losses, Net charge-offs	(1,719)		(925)	(23,810)	(45,692)
Reserve for Unfunded Loan Commitments, Net charge-offs	0		0	0	0
Allowance For Credit Losses, Net charge-offs	(1,719)		(925)	(23,810)	(45,692)
Allowance for Loan and Lease Losses, Provision (negative provision)	11,500			26,274
Reserve for Unfunded Commitments, Provision (negative provision)	0		(546)	(6,726)	(3,286)
Allowance for Credit Losses, Provision (negative provision)	11,500	$ 17,500	15,119	33,000	51,346
Balance, end of period	141,920	132,139		141,920
Reserve for Unfunded Loan Commitments, Balance, end of period	35,361	35,361	20,809	35,361	20,809
Allowance for Credit Losses, Balance, end of period	177,281	$ 167,500	180,415	177,281	180,415
Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, beginning of period			138,879	133,012	143,755
Allowance for Credit Losses, Balance, beginning of period			159,142		161,278
Allowance for Loan and Lease Losses, Charge-offs			(5,928)		(49,807)
Allowance for Credit Losses, Charge-offs			(5,928)		(49,807)
Allowance for Loan and Lease Loss, Recoveries			4,865		9,608
Allowance for Credit Losses, Recoveries			4,865		9,608
Allowance for Loan and Lease Losses, Net charge-offs			(1,063)		(40,199)
Allowance For Credit Losses, Net charge-offs			(1,063)		(40,199)
Allowance for Loan and Lease Losses, Provision (negative provision)			14,954		49,214
Allowance for Credit Losses, Provision (negative provision)			15,500		52,500
Balance, end of period	152,770		152,770	152,770	152,770
Allowance for Credit Losses, Balance, end of period			173,579		173,579
Purchased Credit Impaired Loans and Leases
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, beginning of period				6,444
Balance, beginning of period			7,079		13,483
Allowance for Loan and Lease Losses, Charge-offs			(79)		(5,768)
Allowance for Loan and Lease Loss, Recoveries			217		275
Allowance for Loan and Lease Losses, Net charge-offs			138		(5,493)
Allowance for Loan and Lease Losses, Provision (negative provision)			(381)		(1,154)
Balance, end of period	$ 6,836		$ 6,836	$ 6,836	$ 6,836