Fair Value Schedule of qualitative information on Level 3 measurements (Details) $ in Thousands	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired loans carried at fair value	$ 6,924	$ 2,090
Other Assets, Fair Value Disclosure	7,072,339	6,426,869
Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired loans carried at fair value	6,924	2,090
Other Assets, Fair Value Disclosure	7,072,339	6,426,869
Nonrecurring basis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Assets, Fair Value Disclosure	735	3,033
Nonrecurring basis | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Assets, Fair Value Disclosure	735	3,033
Nonrecurring basis | Residential real estate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Assets, Fair Value Disclosure	735	738
Nonrecurring basis | Residential real estate | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Assets, Fair Value Disclosure	735	738
Nonrecurring basis | Commercial Real Estate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Assets, Fair Value Disclosure	0	2,295
Nonrecurring basis | Commercial Real Estate [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Assets, Fair Value Disclosure	$ 0	$ 2,295
Loans | Commercial Real Estate Portfolio Segment [Member] | Minimum | Fair Value, Inputs, Level 3 [Member] | Measurement Input, Comparability Adjustment [Member] | Valuation, Market Approach [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired Loans Receivable, Measurement Input	0.000	0.000
Loans | Commercial Real Estate Portfolio Segment [Member] | Minimum | Fair Value, Inputs, Level 3 [Member] | Measurement Input, Cap Rate [Member] | Valuation, Income Approach [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired Loans Receivable, Measurement Input	0.093
Loans | Commercial Real Estate Portfolio Segment [Member] | Maximum | Fair Value, Inputs, Level 3 [Member] | Measurement Input, Comparability Adjustment [Member] | Valuation, Market Approach [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired Loans Receivable, Measurement Input	1.390	0.560
Loans | Commercial Real Estate Portfolio Segment [Member] | Maximum | Fair Value, Inputs, Level 3 [Member] | Measurement Input, Comparability Adjustment [Member] | Valuation, Cost Approach [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired Loans Receivable, Measurement Input	0.026	0.931
Loans | Commercial Real Estate Portfolio Segment [Member] | Maximum | Fair Value, Inputs, Level 3 [Member] | Measurement Input, Cap Rate [Member] | Valuation, Income Approach [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired Loans Receivable, Measurement Input	0.200
Loans | Commercial Real Estate Portfolio Segment [Member] | Maximum | Fair Value, Inputs, Level 3 [Member] | MeasurementInputComparabilityAdjustmentMember | Valuation, Cost Approach [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired Loans Receivable, Measurement Input	0.100
Loans | Commercial Real Estate Portfolio Segment [Member] | Weighted Average [Member] | Fair Value, Inputs, Level 3 [Member] | Measurement Input, Comparability Adjustment [Member] | Valuation, Market Approach [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired Loans Receivable, Measurement Input	0.118	0.265
Loans | Commercial Real Estate Portfolio Segment [Member] | Weighted Average [Member] | Fair Value, Inputs, Level 3 [Member] | Measurement Input, Comparability Adjustment [Member] | Valuation, Cost Approach [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired Loans Receivable, Measurement Input	0.026	0.931
Loans | Commercial Real Estate Portfolio Segment [Member] | Weighted Average [Member] | Fair Value, Inputs, Level 3 [Member] | Measurement Input, Cap Rate [Member] | Valuation, Income Approach [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired Loans Receivable, Measurement Input	0.103
Loans | Commercial Real Estate Portfolio Segment [Member] | Weighted Average [Member] | Fair Value, Inputs, Level 3 [Member] | MeasurementInputComparabilityAdjustmentMember | Valuation, Cost Approach [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired Loans Receivable, Measurement Input	0.100
Loans | Residential real estate | Minimum | Fair Value, Inputs, Level 3 [Member] | Measurement Input, Comparability Adjustment [Member] | Valuation, Market Approach [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired Loans Receivable, Measurement Input	0.020	0.000
Loans | Residential real estate | Maximum | Fair Value, Inputs, Level 3 [Member] | Measurement Input, Comparability Adjustment [Member] | Valuation, Market Approach [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired Loans Receivable, Measurement Input	0.478	0.535
Loans | Residential real estate | Weighted Average [Member] | Fair Value, Inputs, Level 3 [Member] | Measurement Input, Comparability Adjustment [Member] | Valuation, Market Approach [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired Loans Receivable, Measurement Input	0.119	0.108
Loans | Nonrecurring basis | Commercial Real Estate Portfolio Segment [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired loans carried at fair value	$ 6,749	$ 1,873
Loans | Nonrecurring basis | Residential real estate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired loans carried at fair value	$ 175	$ 217
Other real estate owned | Residential real estate | Minimum | Fair Value, Inputs, Level 3 [Member] | Measurement Input, Comparability Adjustment [Member] | Valuation, Market Approach [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Real Estate Owned, Measurement Input	0.078	0.046
Other real estate owned | Residential real estate | Maximum | Fair Value, Inputs, Level 3 [Member] | Measurement Input, Comparability Adjustment [Member] | Valuation, Market Approach [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Real Estate Owned, Measurement Input	0.099	0.546
Other real estate owned | Residential real estate | Weighted Average [Member] | Fair Value, Inputs, Level 3 [Member] | Measurement Input, Comparability Adjustment [Member] | Valuation, Market Approach [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Real Estate Owned, Measurement Input	0.089	0.392
Other real estate owned | Commercial Real Estate [Member] | Minimum | Fair Value, Inputs, Level 3 [Member] | Measurement Input, Comparability Adjustment [Member] | Valuation, Market Approach [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Real Estate Owned, Measurement Input		0.009
Other real estate owned | Commercial Real Estate [Member] | Maximum | Fair Value, Inputs, Level 3 [Member] | Measurement Input, Comparability Adjustment [Member] | Valuation, Market Approach [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Real Estate Owned, Measurement Input		0.684
Other real estate owned | Commercial Real Estate [Member] | Maximum | Fair Value, Inputs, Level 3 [Member] | Measurement Input, Cap Rate [Member] | Valuation, Income Approach [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Real Estate Owned, Measurement Input		0.130
Other real estate owned | Commercial Real Estate [Member] | Weighted Average [Member] | Fair Value, Inputs, Level 3 [Member] | Measurement Input, Comparability Adjustment [Member] | Valuation, Market Approach [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Real Estate Owned, Measurement Input		0.347
Other real estate owned | Commercial Real Estate [Member] | Weighted Average [Member] | Fair Value, Inputs, Level 3 [Member] | Measurement Input, Cap Rate [Member] | Valuation, Income Approach [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Real Estate Owned, Measurement Input		0.130
Other real estate owned | Nonrecurring basis | Other Real Estate Owned, Commercial [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Assets, Fair Value Disclosure		$ 2,295
Other real estate owned | Nonrecurring basis | Other Real Estate Owned, Residential [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Assets, Fair Value Disclosure	$ 735	$ 738