Fair Value Qualitative information about Level 3 fair value measurements (Details) $ in Thousands	Jun. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired Loan Fair Value	$ 2,161	$ 2,090
Other Assets, Fair Value Disclosure	7,052,498	6,426,869
Loans Held-for-sale, Fair Value Disclosure	113,275	12,278
Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired Loan Fair Value	2,161	2,090
Other Assets, Fair Value Disclosure	7,052,498	6,426,869
Fair Value, Nonrecurring [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Assets, Fair Value Disclosure	826	3,033
Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Assets, Fair Value Disclosure	826	3,033
Fair Value, Nonrecurring [Member] | Commercial Real Estate Portfolio Segment [Member] | Loans Receivable [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired Loan Fair Value		1,873
Fair Value, Nonrecurring [Member] | Commercial Real Estate Portfolio Segment [Member] | Real Estate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Assets, Fair Value Disclosure		2,295
Fair Value, Nonrecurring [Member] | Residential Real Estate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Assets, Fair Value Disclosure	826	738
Fair Value, Nonrecurring [Member] | Residential Real Estate [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Assets, Fair Value Disclosure	826	738
Fair Value, Nonrecurring [Member] | Residential Real Estate [Member] | Loans Receivable [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired Loan Fair Value		217
Fair Value, Nonrecurring [Member] | Residential Real Estate [Member] | Real Estate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Assets, Fair Value Disclosure	826	738
Estimate of Fair Value Measurement [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired Loan Fair Value		$ 2,090
Estimate of Fair Value Measurement [Member] | Fair Value, Nonrecurring [Member] | Commercial Real Estate Portfolio Segment [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired Loan Fair Value	1,999
Estimate of Fair Value Measurement [Member] | Fair Value, Nonrecurring [Member] | Residential Real Estate [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired Loan Fair Value	$ 162
Measurement Input, Comparability Adjustment [Member] | Commercial Real Estate Portfolio Segment [Member] | Loans Receivable [Member] | Minimum [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired Loans Receivable, Measurement Input	0	0
Measurement Input, Comparability Adjustment [Member] | Commercial Real Estate Portfolio Segment [Member] | Loans Receivable [Member] | Maximum [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired Loans Receivable, Measurement Input	1.390	0.560
Measurement Input, Comparability Adjustment [Member] | Commercial Real Estate Portfolio Segment [Member] | Loans Receivable [Member] | Weighted Average [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired Loans Receivable, Measurement Input	0.213	0.265
Measurement Input, Comparability Adjustment [Member] | Commercial Real Estate Portfolio Segment [Member] | Real Estate [Member] | Minimum [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Real Estate Owned, Measurement Input		0.009
Measurement Input, Comparability Adjustment [Member] | Commercial Real Estate Portfolio Segment [Member] | Real Estate [Member] | Maximum [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Real Estate Owned, Measurement Input		0.684
Measurement Input, Comparability Adjustment [Member] | Commercial Real Estate Portfolio Segment [Member] | Real Estate [Member] | Weighted Average [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Real Estate Owned, Measurement Input		0.347
Measurement Input, Comparability Adjustment [Member] | Residential Real Estate [Member] | Loans Receivable [Member] | Minimum [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired Loans Receivable, Measurement Input	0	0
Measurement Input, Comparability Adjustment [Member] | Residential Real Estate [Member] | Loans Receivable [Member] | Maximum [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired Loans Receivable, Measurement Input	0.550	0.535
Measurement Input, Comparability Adjustment [Member] | Residential Real Estate [Member] | Loans Receivable [Member] | Weighted Average [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired Loans Receivable, Measurement Input	0.144	0.108
Measurement Input, Comparability Adjustment [Member] | Residential Real Estate [Member] | Real Estate [Member] | Minimum [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Real Estate Owned, Measurement Input	0.010	0.046
Measurement Input, Comparability Adjustment [Member] | Residential Real Estate [Member] | Real Estate [Member] | Maximum [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Real Estate Owned, Measurement Input	0.245	0.546
Measurement Input, Comparability Adjustment [Member] | Residential Real Estate [Member] | Real Estate [Member] | Weighted Average [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Real Estate Owned, Measurement Input	0.091	0.392
Measurement Input, Cap Rate [Member] | Commercial Real Estate Portfolio Segment [Member] | Loans Receivable [Member] | Minimum [Member] | Valuation, Income Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired Loans Receivable, Measurement Input	0.200
Measurement Input, Cap Rate [Member] | Commercial Real Estate Portfolio Segment [Member] | Loans Receivable [Member] | Maximum [Member] | Valuation, Income Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired Loans Receivable, Measurement Input	0.200
Measurement Input, Cap Rate [Member] | Commercial Real Estate Portfolio Segment [Member] | Loans Receivable [Member] | Weighted Average [Member] | Valuation, Income Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired Loans Receivable, Measurement Input	0.200
Measurement Input, Cap Rate [Member] | Commercial Real Estate Portfolio Segment [Member] | Real Estate [Member] | Minimum [Member] | Valuation, Income Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Real Estate Owned, Measurement Input		0.130
Measurement Input, Cap Rate [Member] | Commercial Real Estate Portfolio Segment [Member] | Real Estate [Member] | Maximum [Member] | Valuation, Income Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Real Estate Owned, Measurement Input		0.130
Measurement Input, Cap Rate [Member] | Commercial Real Estate Portfolio Segment [Member] | Real Estate [Member] | Weighted Average [Member] | Valuation, Income Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Real Estate Owned, Measurement Input		0.130
Measurement input replacement cost [Member] | Commercial Real Estate Portfolio Segment [Member] | Loans Receivable [Member] | Minimum [Member] | Valuation, Cost Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired Loans Receivable, Measurement Input		0.931
Measurement input replacement cost [Member] | Commercial Real Estate Portfolio Segment [Member] | Loans Receivable [Member] | Maximum [Member] | Valuation, Cost Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired Loans Receivable, Measurement Input		0.931
Measurement input replacement cost [Member] | Commercial Real Estate Portfolio Segment [Member] | Loans Receivable [Member] | Weighted Average [Member] | Valuation, Cost Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired Loans Receivable, Measurement Input		0.931