Loans and the Allowance for Loan Losses (Details) - Loans receivable on nonaccrual status - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Loans and the Allowance for Loan and Lease Losses (Details) - Loans receivable on nonaccrual status [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	$ 65,613	$ 5,734
Commercial Portfolio Segment [Member]
Loans and the Allowance for Loan and Lease Losses (Details) - Loans receivable on nonaccrual status [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	47,363	1,460
Commercial Real Estate Portfolio Segment [Member]
Loans and the Allowance for Loan and Lease Losses (Details) - Loans receivable on nonaccrual status [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	12,757	1,081
Construction Loans [Member]
Loans and the Allowance for Loan and Lease Losses (Details) - Loans receivable on nonaccrual status [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status
Residential Portfolio Segment [Member]
Loans and the Allowance for Loan and Lease Losses (Details) - Loans receivable on nonaccrual status [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	$ 5,493	$ 3,193