Loans and Allowance for Credit Losses Troubled Debt Restructuring Modification (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) loans	Dec. 31, 2019 USD ($) loans	Dec. 31, 2018 USD ($) loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of loans modified during the year (loans) | loans	142	83	117
Post-Modification Recorded Investment | $	$ 45,283	$ 10,599	$ 18,375
Real estate - commercial mortgage
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of loans modified during the year (loans) | loans	12	2	6
Post-Modification Recorded Investment | $	$ 24,868	$ 263	$ 8,261
Commercial - secured
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of loans modified during the year (loans) | loans	20	16	8
Post-Modification Recorded Investment | $	$ 5,218	$ 5,378	$ 4,226
Real estate - residential mortgage
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of loans modified during the year (loans) | loans	48	6	7
Post-Modification Recorded Investment | $	$ 10,493	$ 2,252	$ 801
Real estate - home equity
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of loans modified during the year (loans) | loans	48	59	96
Post-Modification Recorded Investment | $	$ 4,359	$ 2,706	$ 5,087
Consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of loans modified during the year (loans) | loans	14	0	0
Post-Modification Recorded Investment | $	$ 345	$ 0	$ 0