Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Details Textuals) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Allowances and Reserve Balance	$ 47,776,000	$ 21,907,000
Expense Related to Qualified Affordable Housing Projects	23,000,000	19,000,000	$ 17,000,000
Remaining Investment in Qualified Affordable Housing Projects	268,000,000	234,000,000
Unfunded Equity Contributions Obligation Amount	118,000,000	123,000,000
Loans repurchased under make whole requests	$ 10,000,000	$ 2,000,000
Loans Sold To Outside Investors Loss Reimbursement Settlement Paid	no	negligible
Loans sold to outside investors original amount	$ 14,400,000,000
Loans sold to outside investors remaining outstanding amount	6,800,000,000
Mortgage Repurchase Reserve	2,000,000	$ 795,000
Residential mortgage loans sold with recourse risk	36,000,000	39,000,000
Residential mortgage loans sold with credit recourse risk	33,000,000	45,000,000
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member]
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Allowances and Reserve Balance		21,907,000	$ 24,336,000
Community Reinvestment, Obtaining Tax Credits, and Other Tax Benefits [Member]
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Carrying value of investments	272,000,000	248,000,000
Tax Credit and Other Investments
Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Textuals) [Line Items]
Carrying value of investments	$ 25,000,000	$ 26,000,000