Allowance for Loan Losses Allowance Text (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Allowance	$ 74,742,000	$ 78,077,000	$ 78,500,000	$ 75,838,000
Loans and Leases Receivable, Net of Deferred Income	6,505,028,000	6,114,354,000
Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Net of Deferred Income	$ 0	$ 0