Loans (Summary of Recorded Investment of Consumer Loans by Risk Rating Categories) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 12,990,779	$ 7,271,147
Residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Loans		1,429,636
Consumer installment
Financing Receivable, Recorded Investment [Line Items]
Loans		877,457
Home equity
Financing Receivable, Recorded Investment [Line Items]
Loans		713,937
Consumer Loan Portfolio
Financing Receivable, Recorded Investment [Line Items]
Loans	5,396,567	3,021,030
Consumer Loan Portfolio | Residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Loans	3,086,474	1,429,636
Consumer Loan Portfolio | Consumer installment
Financing Receivable, Recorded Investment [Line Items]
Loans	1,433,884	877,457
Consumer Loan Portfolio | Home equity
Financing Receivable, Recorded Investment [Line Items]
Loans	876,209	713,937
Consumer Originated Portfolio
Financing Receivable, Recorded Investment [Line Items]
Loans	3,353,352	2,677,213
Consumer Originated Portfolio | Performing
Financing Receivable, Recorded Investment [Line Items]
Loans	3,342,153	2,669,226
Consumer Originated Portfolio | Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Loans	11,199	7,987
Consumer Originated Portfolio | Residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Loans	1,475,342	1,216,975
Consumer Originated Portfolio | Residential mortgage | Performing
Financing Receivable, Recorded Investment [Line Items]
Loans	1,468,373	1,211,418
Consumer Originated Portfolio | Residential mortgage | Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Loans	6,969	5,557
Consumer Originated Portfolio | Consumer installment
Financing Receivable, Recorded Investment [Line Items]
Loans	1,282,588	869,426
Consumer Originated Portfolio | Consumer installment | Performing
Financing Receivable, Recorded Investment [Line Items]
Loans	1,281,709	868,975
Consumer Originated Portfolio | Consumer installment | Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Loans	879	451
Consumer Originated Portfolio | Home equity
Financing Receivable, Recorded Investment [Line Items]
Loans	595,422	590,812
Consumer Originated Portfolio | Home equity | Performing
Financing Receivable, Recorded Investment [Line Items]
Loans	592,071	588,833
Consumer Originated Portfolio | Home equity | Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Loans	3,351	1,979
Consumer Acquired Portfolio
Financing Receivable, Recorded Investment [Line Items]
Loans	2,043,215	343,817
Consumer Acquired Portfolio | Residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Loans	1,611,132	212,661
Consumer Acquired Portfolio | Consumer installment
Financing Receivable, Recorded Investment [Line Items]
Loans	151,296	8,031
Consumer Acquired Portfolio | Home equity
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 280,787	$ 123,125