Loans (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) contract agreement	Dec. 31, 2015 USD ($) contract
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	$ 317,970	$ 159,713
TDRs both accruing and nonaccruing	121,700	13,100
Post-Modification outstanding recorded investment	$ 132,234	$ 5,107
Number of TDRs subsequently defaulted | contract	0	0
TDRs and loans impaired with minimum aggregate relationship balances	$ 1,000
Recovery period	3 years
Percentage of recoveries on reimbursed losses due to FDIC	80.00%
Loans covered by loss share agreement	$ 149,000
Real estate acquired through foreclosure	18,884	$ 26,256
Related party balances of loans	15,300	17,400
Related party new loans	25,500
Related party repayments	27,600
Loans held for sale	34,064	20,434
Short-term borrowings	1,225,406	1,423,644
FHLB Borrowings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Short-term borrowings	865,000	900,000
Troubled Debt Restructurings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	81,900	8,800
Troubled Debt Restructurings [Member] | Loans With Extended Amortization Terms Or Other Payment Concessions [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Post-Modification outstanding recorded investment	108,900	5,000
Troubled Debt Restructurings [Member] | Loans With Significant Covenant Waivers [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Post-Modification outstanding recorded investment	22,800
Troubled Debt Restructurings [Member] | Loans With Other Modifications [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Post-Modification outstanding recorded investment	$ 500	100
FDIC Loss Share Agreement [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loss share agreements | agreement	2
Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	$ 12,351	9,061
Post-Modification outstanding recorded investment		20
Real estate in process of foreclosure	10,100	7,400
Real estate acquired through foreclosure	3,100	9,300
Consumer [Member] | FDIC Loss Share Agreement [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Real estate in process of foreclosure	4,900	4,100
Real estate acquired through foreclosure	$ 900	$ 1,600