Loans Loans - Weighted Average Risk Grade for All Commercial Loans by Class and Year of Origination (Details) $ in Thousands	Sep. 30, 2021 USD ($) Grade	Dec. 31, 2020 USD ($) Grade
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	$ 15,832,670	$ 17,481,309
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	1,049,079
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	789,321
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	451,895
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	237,283
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	178,027
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	168,701
Financing Receivable, Revolving	1,968,118
Loans and Leases Receivable, Net of Deferred Income	$ 4,929,656	$ 4,955,341
Weighted Average Risk Grade For Loans | Grade	6.29	6.45
Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 394,708
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	13,034
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	37,051
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	11,118
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	3,958
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	6,151
Financing Receivable, Revolving	434,826
Loans and Leases Receivable, Net of Deferred Income	$ 978,211	$ 1,235,198
Weighted Average Risk Grade For Loans | Grade	6.55	6.85
Commercial Real Estate Buildings Land And Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 1,187,521
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,328,713
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	1,016,891
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	687,482
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	647,625
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	975,874
Financing Receivable, Revolving	52,194
Loans and Leases Receivable, Net of Deferred Income	$ 5,984,390	$ 5,796,653
Weighted Average Risk Grade For Loans | Grade	7.27	7.34
Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 467,103
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	317,783
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	299,927
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	20,457
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	513
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	2,593
Financing Receivable, Revolving	158,257
Loans and Leases Receivable, Net of Deferred Income	$ 1,266,633	$ 1,223,814
Weighted Average Risk Grade For Loans | Grade	7.16	7.22
Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 1,654,624
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,646,496
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	1,316,818
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	707,939
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	648,138
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	978,467
Financing Receivable, Revolving	210,451
Loans and Leases Receivable, Net of Deferred Income	$ 7,251,023	$ 7,020,467
Weighted Average Risk Grade For Loans | Grade	7.25	7.32
Risk Grade One To Eight [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 1,009,752
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	730,976
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	405,216
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	201,578
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	160,431
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	149,611
Financing Receivable, Revolving	1,875,496
Loans and Leases Receivable, Net of Deferred Income	$ 4,598,663	$ 4,506,121
Weighted Average Risk Grade For Loans | Grade	6.04	6.13
Risk Grade One To Eight [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 350,757
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	10,562
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	10,339
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	7,060
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	3,958
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	4,518
Financing Receivable, Revolving	392,527
Loans and Leases Receivable, Net of Deferred Income	$ 848,158	$ 968,144
Weighted Average Risk Grade For Loans | Grade	5.94	5.99
Risk Grade One To Eight [Member] | Commercial Real Estate Buildings Land And Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 1,153,181
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,146,764
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	862,629
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	578,768
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	517,822
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	842,409
Financing Receivable, Revolving	44,525
Loans and Leases Receivable, Net of Deferred Income	$ 5,221,458	$ 5,047,873
Weighted Average Risk Grade For Loans | Grade	6.90	6.97
Risk Grade One To Eight [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 429,990
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	284,149
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	299,927
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	20,457
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	2,593
Financing Receivable, Revolving	144,950
Loans and Leases Receivable, Net of Deferred Income	$ 1,182,066	$ 1,110,025
Weighted Average Risk Grade For Loans | Grade	7.03	6.99
Risk Grade One To Eight [Member] | Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income		$ 6,157,898
Weighted Average Risk Grade For Loans | Grade		6.98
Risk Grade Nine [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 9,569
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	35,274
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	30,953
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	26,216
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	12,258
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	18,329
Financing Receivable, Revolving	70,412
Loans and Leases Receivable, Net of Deferred Income	$ 208,283	$ 256,198
Weighted Average Risk Grade For Loans | Grade	9.00	9.00
Risk Grade Nine [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 32,434
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	712
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	1,831
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	270
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	737
Financing Receivable, Revolving	10,136
Loans and Leases Receivable, Net of Deferred Income	$ 48,694	$ 133,547
Weighted Average Risk Grade For Loans | Grade	9.00	9.00
Risk Grade Nine [Member] | Commercial Real Estate Buildings Land And Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 13,873
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	143,504
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	70,218
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	48,372
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	29,691
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	34,746
Financing Receivable, Revolving	4,669
Loans and Leases Receivable, Net of Deferred Income	$ 351,931	$ 325,227
Weighted Average Risk Grade For Loans | Grade	9.00	9.00
Risk Grade Nine [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 37,113
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	32,002
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	513
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Revolving	13,307
Loans and Leases Receivable, Net of Deferred Income	$ 82,935	$ 72,287
Weighted Average Risk Grade For Loans | Grade	9.00	9.00
Risk Grade Nine [Member] | Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income		$ 397,514
Weighted Average Risk Grade For Loans | Grade		9.00
Risk Grade Ten [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 28,117
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	6,546
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	1,871
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	4,653
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	1,358
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	112
Financing Receivable, Revolving	12,954
Loans and Leases Receivable, Net of Deferred Income	$ 57,263	$ 125,977
Weighted Average Risk Grade For Loans | Grade	10.00	10.00
Risk Grade Ten [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	115
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	703
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	668
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Revolving	860
Loans and Leases Receivable, Net of Deferred Income	$ 2,824	$ 46,427
Weighted Average Risk Grade For Loans | Grade	10.00	10.00
Risk Grade Ten [Member] | Commercial Real Estate Buildings Land And Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 14,376
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	16,956
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	69,882
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	51,903
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	65,363
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	55,732
Financing Receivable, Revolving	0
Loans and Leases Receivable, Net of Deferred Income	$ 274,212	$ 258,454
Weighted Average Risk Grade For Loans | Grade	10.00	10.00
Risk Grade Ten [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Revolving	0
Loans and Leases Receivable, Net of Deferred Income	$ 0	$ 38,962
Weighted Average Risk Grade For Loans | Grade	10.00	10.00
Risk Grade Ten [Member] | Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income		$ 297,416
Weighted Average Risk Grade For Loans | Grade		10.00
Risk Grade Eleven [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 1,326
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	8,603
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	9,644
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	4,160
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	3,098
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	279
Financing Receivable, Revolving	7,189
Loans and Leases Receivable, Net of Deferred Income	$ 46,098	$ 47,196
Weighted Average Risk Grade For Loans | Grade	11.00	11.00
Risk Grade Eleven [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 11,517
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,168
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	17,711
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	1,607
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	573
Financing Receivable, Revolving	19,133
Loans and Leases Receivable, Net of Deferred Income	$ 55,188	$ 63,912
Weighted Average Risk Grade For Loans | Grade	11.00	11.00
Risk Grade Eleven [Member] | Commercial Real Estate Buildings Land And Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 3,995
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	19,766
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	11,351
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	7,615
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	32,698
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	40,245
Financing Receivable, Revolving	3,000
Loans and Leases Receivable, Net of Deferred Income	$ 124,542	$ 149,362
Weighted Average Risk Grade For Loans | Grade	11.00	11.00
Risk Grade Eleven [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Revolving	0
Loans and Leases Receivable, Net of Deferred Income	$ 0	$ 856
Weighted Average Risk Grade For Loans | Grade	11.00	11.00
Risk Grade Eleven [Member] | Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income		$ 150,218
Weighted Average Risk Grade For Loans | Grade		11.00
Risk Grade Twelve [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 135
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	7,922
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	3,263
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	676
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	411
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	370
Financing Receivable, Revolving	962
Loans and Leases Receivable, Net of Deferred Income	$ 15,713	$ 14,528
Weighted Average Risk Grade For Loans | Grade	12.00	12.00
Risk Grade Twelve [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	34
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	4,777
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	90
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	323
Financing Receivable, Revolving	4,641
Loans and Leases Receivable, Net of Deferred Income	$ 9,964	$ 13,741
Weighted Average Risk Grade For Loans | Grade	12.00	12.00
Risk Grade Twelve [Member] | Commercial Real Estate Buildings Land And Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 1,896
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,723
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	2,511
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	824
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	2,051
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	2,492
Financing Receivable, Revolving	0
Loans and Leases Receivable, Net of Deferred Income	$ 11,497	$ 15,224
Weighted Average Risk Grade For Loans | Grade	12.00	12.00
Risk Grade Twelve [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,432
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Revolving	0
Loans and Leases Receivable, Net of Deferred Income	$ 1,432	$ 1,684
Weighted Average Risk Grade For Loans | Grade	12.00	12.00
Risk Grade Twelve [Member] | Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income		$ 16,908
Weighted Average Risk Grade For Loans | Grade		12.00
Risk Grade Thirteen [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 180
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	948
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	471
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Revolving	1,105
Loans and Leases Receivable, Net of Deferred Income	$ 3,636	$ 5,321
Weighted Average Risk Grade For Loans | Grade	13.00	13.00
Risk Grade Thirteen [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	443
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	1,690
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	1,423
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Revolving	7,529
Loans and Leases Receivable, Net of Deferred Income	$ 13,383	$ 9,427
Weighted Average Risk Grade For Loans | Grade	13.00	13.00
Risk Grade Thirteen [Member] | Commercial Real Estate Buildings Land And Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 200
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	300
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	250
Financing Receivable, Revolving	0
Loans and Leases Receivable, Net of Deferred Income	$ 750	$ 513
Weighted Average Risk Grade For Loans | Grade	13.00	13.00
Risk Grade Thirteen [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	200
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Revolving	0
Loans and Leases Receivable, Net of Deferred Income	$ 200	$ 0
Weighted Average Risk Grade For Loans | Grade	13.00	13.00
Risk Grade Thirteen [Member] | Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income		$ 513
Weighted Average Risk Grade For Loans | Grade		13.00
Revolving Credit Facility [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	6.17
Revolving Credit Facility [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	6.26
Revolving Credit Facility [Member] | Commercial Real Estate Buildings Land And Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	7.30
Revolving Credit Facility [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	7.24
Revolving Credit Facility [Member] | Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	7.26
Revolving Loans Converted to Term [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Revolving, Converted to Term Loan	$ 87,232
Weighted Average Risk Grade For Loans | Grade	7.60
Revolving Loans Converted to Term [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Revolving, Converted to Term Loan	$ 77,365
Weighted Average Risk Grade For Loans | Grade	6.76
Revolving Loans Converted to Term [Member] | Commercial Real Estate Buildings Land And Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Revolving, Converted to Term Loan	$ 88,090
Weighted Average Risk Grade For Loans | Grade	7.15
Revolving Loans Converted to Term [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Revolving, Converted to Term Loan	$ 0
Weighted Average Risk Grade For Loans | Grade	0
Revolving Loans Converted to Term [Member] | Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Revolving, Converted to Term Loan	$ 88,090
Weighted Average Risk Grade For Loans | Grade	7.15
Revolving Loans Converted to Term [Member] | Risk Grade One To Eight [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Revolving, Converted to Term Loan	$ 65,603
Revolving Loans Converted to Term [Member] | Risk Grade One To Eight [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Revolving, Converted to Term Loan	68,437
Revolving Loans Converted to Term [Member] | Risk Grade One To Eight [Member] | Commercial Real Estate Buildings Land And Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Revolving, Converted to Term Loan	75,360
Revolving Loans Converted to Term [Member] | Risk Grade One To Eight [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Revolving, Converted to Term Loan	0
Revolving Loans Converted to Term [Member] | Risk Grade Nine [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Revolving, Converted to Term Loan	5,272
Revolving Loans Converted to Term [Member] | Risk Grade Nine [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Revolving, Converted to Term Loan	2,574
Revolving Loans Converted to Term [Member] | Risk Grade Nine [Member] | Commercial Real Estate Buildings Land And Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Revolving, Converted to Term Loan	6,858
Revolving Loans Converted to Term [Member] | Risk Grade Nine [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Revolving, Converted to Term Loan	0
Revolving Loans Converted to Term [Member] | Risk Grade Ten [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Revolving, Converted to Term Loan	1,652
Revolving Loans Converted to Term [Member] | Risk Grade Ten [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Revolving, Converted to Term Loan	478
Revolving Loans Converted to Term [Member] | Risk Grade Ten [Member] | Commercial Real Estate Buildings Land And Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Revolving, Converted to Term Loan	0
Revolving Loans Converted to Term [Member] | Risk Grade Ten [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Revolving, Converted to Term Loan	0
Revolving Loans Converted to Term [Member] | Risk Grade Eleven [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Revolving, Converted to Term Loan	11,799
Revolving Loans Converted to Term [Member] | Risk Grade Eleven [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Revolving, Converted to Term Loan	3,479
Revolving Loans Converted to Term [Member] | Risk Grade Eleven [Member] | Commercial Real Estate Buildings Land And Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Revolving, Converted to Term Loan	5,872
Revolving Loans Converted to Term [Member] | Risk Grade Eleven [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Revolving, Converted to Term Loan	0
Revolving Loans Converted to Term [Member] | Risk Grade Twelve [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Revolving, Converted to Term Loan	1,974
Revolving Loans Converted to Term [Member] | Risk Grade Twelve [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Revolving, Converted to Term Loan	99
Revolving Loans Converted to Term [Member] | Risk Grade Twelve [Member] | Commercial Real Estate Buildings Land And Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Revolving, Converted to Term Loan	0
Revolving Loans Converted to Term [Member] | Risk Grade Twelve [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Revolving, Converted to Term Loan	0
Revolving Loans Converted to Term [Member] | Risk Grade Thirteen [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Revolving, Converted to Term Loan	932
Revolving Loans Converted to Term [Member] | Risk Grade Thirteen [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Revolving, Converted to Term Loan	2,298
Revolving Loans Converted to Term [Member] | Risk Grade Thirteen [Member] | Commercial Real Estate Buildings Land And Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Revolving, Converted to Term Loan	0
Revolving Loans Converted to Term [Member] | Risk Grade Thirteen [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Revolving, Converted to Term Loan	$ 0
2021 [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	5.97
2021 [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	6.37
2021 [Member] | Commercial Real Estate Buildings Land And Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	7.21
2021 [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	7.13
2021 [Member] | Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	7.19
2020 [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	6.35
2020 [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	8.13
2020 [Member] | Commercial Real Estate Buildings Land And Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	7.27
2020 [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	6.87
2020 [Member] | Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	7.19
2019 [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	6.91
2019 [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	9.98
2019 [Member] | Commercial Real Estate Buildings Land And Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	7.40
2019 [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	7.46
2019 [Member] | Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	7.41
2018 [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	7.04
2018 [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	8.77
2018 [Member] | Commercial Real Estate Buildings Land And Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	7.37
2018 [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	7.45
2018 [Member] | Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	7.38
2017 [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	6.20
2017 [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	7.19
2017 [Member] | Commercial Real Estate Buildings Land And Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	7.38
2017 [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	9.00
2017 [Member] | Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	7.38
Prior Years [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	5.94
Prior Years [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	7.84
Prior Years [Member] | Commercial Real Estate Buildings Land And Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	7.04
Prior Years [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	6.79
Prior Years [Member] | Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	7.04