Commitments, Off-Balance Sheet Arrangements, Legal Proceedings and Regulatory Matters (Details Textuals) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Unfunded Commitments	$ 26,000		$ 24,000
Expense Related to Qualified Affordable Housing Projects	5,000	$ 5,000
Remaining Investment in Qualified Affordable Housing Projects	160,000		132,000
Variable Interest Entity Reporting Entity Involvement Unfunded Obligation Amount	73,000		51,000
Loans Repurchased Under Make Whole Requests	$ 305		$ 2,000
Loans Sold To Outside Investors Loss ReimbursementSettlement Paid	negligible		negligible
Loans Sold To Outside Investors Original Amount	$ 11,300,000
Loans Sold To Outside Investors Remaining Outstanding Amount	7,300,000
Residential Mortgage Loans Sold With Recourse Risk	31,000		$ 47,000
Residential Mortgage Loans Sold With Credit Recourse Risk	54,000		57,000
UnconsolidatedProjectsLowIncomeHousing [Member]
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Other Investments	169,000		136,000
PrincipalInvestmentCommitment [Member]
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Other Investments	25,000		25,000
Standby Letters of Credit
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Lines of Credit, Fair Value Disclosure	$ 2,000		$ 2,000