Allowance for Loan Losses Allowance for Loan Losses Text Disclosures (Details) - USD ($)	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Net of Deferred Income	$ 6,250,217,000	$ 6,114,354,000
Loans and Leases Receivable, Allowance	78,031,000	78,077,000	$ 76,427,000	$ 78,500,000
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