Loans Loans - Weighted Average Risk Grade for All Commercial Loans by Class and Year of Origination (Details) $ in Thousands	Jun. 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	$ 16,596,326	$ 17,481,309
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	742,844
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	834,516
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	511,102
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	276,574
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	200,227
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	190,390
Financing Receivable, Revolving	1,907,724
Loans and Leases Receivable, Net of Deferred Income	$ 4,755,345	$ 4,955,341
Weighted Average Risk Grade For Loans | Grade	6.32	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	$ 415,757
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	14,088
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	41,212
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	12,931
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	6,623
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	6,412
Financing Receivable, Revolving	495,458
Loans and Leases Receivable, Net of Deferred Income	$ 1,023,202	$ 1,235,198
Weighted Average Risk Grade For Loans | Grade	6.73	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	$ 738,386
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,455,839
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	1,031,482
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	747,435
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	687,351
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	1,086,426
Financing Receivable, Revolving	58,703
Loans and Leases Receivable, Net of Deferred Income	$ 5,889,737	$ 5,796,653
Weighted Average Risk Grade For Loans | Grade	7.28	7.34
Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 298,862
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	294,840
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	367,127
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	48,269
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	542
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	2,646
Financing Receivable, Revolving	154,023
Loans and Leases Receivable, Net of Deferred Income	$ 1,166,309	$ 1,223,814
Weighted Average Risk Grade For Loans | Grade	7.17	7.22
Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 1,037,248
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,750,679
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	1,398,609
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	795,704
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	687,893
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	1,089,072
Financing Receivable, Revolving	212,726
Loans and Leases Receivable, Net of Deferred Income	$ 7,056,046	$ 7,020,467
Weighted Average Risk Grade For Loans | Grade	7.26	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	$ 704,030
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	757,923
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	458,789
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	231,663
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	178,242
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	177,200
Financing Receivable, Revolving	1,796,022
Loans and Leases Receivable, Net of Deferred Income	$ 4,373,376	$ 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	$ 368,434
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	11,610
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	13,300
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	8,067
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	6,623
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	4,734
Financing Receivable, Revolving	430,760
Loans and Leases Receivable, Net of Deferred Income	$ 859,463	$ 968,144
Weighted Average Risk Grade For Loans | Grade	6.03	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	$ 707,609
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,258,571
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	920,940
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	625,954
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	548,979
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	923,486
Financing Receivable, Revolving	51,468
Loans and Leases Receivable, Net of Deferred Income	$ 5,107,543	$ 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	$ 295,583
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	262,942
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	364,655
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	48,269
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	2,646
Financing Receivable, Revolving	140,472
Loans and Leases Receivable, Net of Deferred Income	$ 1,114,567	$ 1,110,025
Weighted Average Risk Grade For Loans | Grade	7.08	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	$ 11,275
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	49,069
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	36,452
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	32,061
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	15,796
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	12,166
Financing Receivable, Revolving	75,803
Loans and Leases Receivable, Net of Deferred Income	$ 240,055	$ 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	$ 34,516
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	806
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	2,041
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	986
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	22,953
Loans and Leases Receivable, Net of Deferred Income	$ 66,359	$ 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	$ 22,692
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	155,019
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	68,831
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	48,895
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	38,034
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	33,759
Financing Receivable, Revolving	4,235
Loans and Leases Receivable, Net of Deferred Income	$ 373,909	$ 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	$ 3,279
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	30,231
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	2,472
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	542
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Revolving	13,551
Loans and Leases Receivable, Net of Deferred Income	$ 50,075	$ 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	$ 26,973
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	8,903
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	1,861
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	6,903
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	2,138
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	157
Financing Receivable, Revolving	18,781
Loans and Leases Receivable, Net of Deferred Income	$ 68,734	$ 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	$ 1,267
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	127
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	767
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	1,057
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	742
Financing Receivable, Revolving	1,493
Loans and Leases Receivable, Net of Deferred Income	$ 9,065	$ 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	$ 5,642
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	19,719
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	25,328
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	59,859
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	65,261
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	72,057
Financing Receivable, Revolving	0
Loans and Leases Receivable, Net of Deferred Income	$ 253,053	$ 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	$ 566
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	9,716
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	11,697
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	5,006
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	3,016
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	788
Financing Receivable, Revolving	16,790
Loans and Leases Receivable, Net of Deferred Income	$ 57,011	$ 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	$ 11,540
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,022
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	18,249
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	1,163
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	601
Financing Receivable, Revolving	26,307
Loans and Leases Receivable, Net of Deferred Income	$ 62,532	$ 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	$ 897
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	20,635
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	13,461
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	11,885
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	32,984
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	53,242
Financing Receivable, Revolving	3,000
Loans and Leases Receivable, Net of Deferred Income	$ 142,052	$ 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	$ 0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	6,325
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	1,759
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	941
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	560
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	79
Financing Receivable, Revolving	328
Loans and Leases Receivable, Net of Deferred Income	$ 12,343	$ 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	42
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	5,165
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	235
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	335
Financing Receivable, Revolving	6,093
Loans and Leases Receivable, Net of Deferred Income	$ 11,973	$ 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	$ 1,346
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,895
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	2,622
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	842
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	2,093
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	3,632
Financing Receivable, Revolving	0
Loans and Leases Receivable, Net of Deferred Income	$ 12,430	$ 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	1,467
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	$ 1,467	$ 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	$ 0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	2,580
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	544
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	475
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Revolving	0
Loans and Leases Receivable, Net of Deferred Income	$ 3,826	$ 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	481
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	7,852
Loans and Leases Receivable, Net of Deferred Income	$ 13,810	$ 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	6.19
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	6.58
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	7.20
Revolving Credit Facility [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	7.14
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	7.16
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	$ 91,968
Weighted Average Risk Grade For Loans | Grade	7.36
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	$ 30,721
Weighted Average Risk Grade For Loans | Grade	8.80
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	$ 84,115
Weighted Average Risk Grade For Loans | Grade	7.31
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	$ 84,115
Weighted Average Risk Grade For Loans | Grade	7.31
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	$ 69,507
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	15,935
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	70,536
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	7,433
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	5,057
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	2,444
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	3,018
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	3,612
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	5,187
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	9,432
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	3,650
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	5,948
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	2,351
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	103
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	227
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	2,364
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	5.80
2021 [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	6.31
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	7.20
2021 [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	7.05
2021 [Member] | Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	7.16
2020 [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	6.42
2020 [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	8.09
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	6.99
2020 [Member] | Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	7.23
2019 [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	6.89
2019 [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	9.85
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	7.28
2019 [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	7.35
2019 [Member] | Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	7.30
2018 [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	7.16
2018 [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	8.63
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	7.47
2018 [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	7.73
2018 [Member] | Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	7.48
2017 [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	6.26
2017 [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	7.40
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	7.39
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	7.39
Prior Years [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	5.92
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	7.95
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	7.13
Prior Years [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	6.78
Prior Years [Member] | Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade For Loans | Grade	7.13