Loans Loans - Age Analysis of Past Due Consumer Loans,Segregated by Class and Year of Origination (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	$ 116,865
Current Loans	15,715,805
Loans and Leases Receivable, Net of Deferred Income	15,832,670	$ 17,481,309
Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	6,249
Current Loans	1,356,790
Loans and Leases Receivable, Net of Deferred Income	1,363,039	1,330,774
Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	4,707
Current Loans	478,214
Loans and Leases Receivable, Net of Deferred Income	482,921	$ 505,680
Financing Receivables, 30 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	72,678
Financing Receivables, 30 to 89 Days Past Due [Member] | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	4,148
Financing Receivables, 30 to 89 Days Past Due [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	3,678
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	44,187
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	2,101
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	1,029
Revolving Credit Facility [Member] | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	1,141
Current Loans	464,440
Loans and Leases Receivable, Net of Deferred Income	465,581
Revolving Credit Facility [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	481
Current Loans	374,993
Loans and Leases Receivable, Net of Deferred Income	375,474
Revolving Credit Facility [Member] | Financing Receivables, 30 to 89 Days Past Due [Member] | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	174
Revolving Credit Facility [Member] | Financing Receivables, 30 to 89 Days Past Due [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	481
Revolving Credit Facility [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	967
Revolving Credit Facility [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	0
Revolving Loans Converted to Term [Member] | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	1,526
Current Loans	11,972
Loans and Leases Receivable, Net of Deferred Income	13,498
Revolving Loans Converted to Term [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	1,388
Current Loans	26,196
Loans and Leases Receivable, Net of Deferred Income	27,584
Revolving Loans Converted to Term [Member] | Financing Receivables, 30 to 89 Days Past Due [Member] | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	1,384
Revolving Loans Converted to Term [Member] | Financing Receivables, 30 to 89 Days Past Due [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	1,035
Revolving Loans Converted to Term [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	142
Revolving Loans Converted to Term [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	353
2021 [Member] | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	396
Current Loans	235,725
Loans and Leases Receivable, Net of Deferred Income	236,121
2021 [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	2,103
Current Loans	39,156
Loans and Leases Receivable, Net of Deferred Income	41,259
2021 [Member] | Financing Receivables, 30 to 89 Days Past Due [Member] | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	396
2021 [Member] | Financing Receivables, 30 to 89 Days Past Due [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	1,527
2021 [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	0
2021 [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	576
2020 [Member] | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	34
Current Loans	283,853
Loans and Leases Receivable, Net of Deferred Income	283,887
2020 [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	293
Current Loans	20,924
Loans and Leases Receivable, Net of Deferred Income	21,217
2020 [Member] | Financing Receivables, 30 to 89 Days Past Due [Member] | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	34
2020 [Member] | Financing Receivables, 30 to 89 Days Past Due [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	283
2020 [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	0
2020 [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	10
2019 [Member] | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	387
Current Loans	111,449
Loans and Leases Receivable, Net of Deferred Income	111,836
2019 [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	182
Current Loans	10,442
Loans and Leases Receivable, Net of Deferred Income	10,624
2019 [Member] | Financing Receivables, 30 to 89 Days Past Due [Member] | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	277
2019 [Member] | Financing Receivables, 30 to 89 Days Past Due [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	182
2019 [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	110
2019 [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	0
2018 [Member] | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	381
Current Loans	62,416
Loans and Leases Receivable, Net of Deferred Income	62,797
2018 [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	179
Current Loans	3,268
Loans and Leases Receivable, Net of Deferred Income	3,447
2018 [Member] | Financing Receivables, 30 to 89 Days Past Due [Member] | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	370
2018 [Member] | Financing Receivables, 30 to 89 Days Past Due [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	89
2018 [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	11
2018 [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	90
2017 [Member] | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	552
Current Loans	54,827
Loans and Leases Receivable, Net of Deferred Income	55,379
2017 [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	63
Current Loans	1,844
Loans and Leases Receivable, Net of Deferred Income	1,907
2017 [Member] | Financing Receivables, 30 to 89 Days Past Due [Member] | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	326
2017 [Member] | Financing Receivables, 30 to 89 Days Past Due [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	63
2017 [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	226
2017 [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	0
Prior Years [Member] | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	1,832
Current Loans	132,108
Loans and Leases Receivable, Net of Deferred Income	133,940
Prior Years [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	18
Current Loans	1,391
Loans and Leases Receivable, Net of Deferred Income	1,409
Prior Years [Member] | Financing Receivables, 30 to 89 Days Past Due [Member] | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	1,187
Prior Years [Member] | Financing Receivables, 30 to 89 Days Past Due [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	18
Prior Years [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	645
Prior Years [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due Loans	$ 0