Loans and Allowances for Credit Losses, Nonaccrual (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual	$ 134,059	$ 234,693
Financing Receivable, Nonaccrual, No Allowance	114,025	167,878
Financing receivable, Nonaccrual, With Allowance	20,034	66,815
Financing Receivable, Nonaccrual, Related Allowance	6,343	22,441
Commercial [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual	74,104	167,159
Financing Receivable, Nonaccrual, No Allowance	62,146	113,945
Financing receivable, Nonaccrual, With Allowance	11,958	53,214
Financing Receivable, Nonaccrual, Related Allowance	3,994	19,052
Commercial [Member] | Energy [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual	31,091	125,059
Financing Receivable, Nonaccrual, No Allowance	31,091	76,633
Financing receivable, Nonaccrual, With Allowance	0	48,426
Financing Receivable, Nonaccrual, Related Allowance	0	16,478
Commercial [Member] | Healthcare [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual	15,762	3,645
Financing Receivable, Nonaccrual, No Allowance	9,679	3,645
Financing receivable, Nonaccrual, With Allowance	6,083	0
Financing Receivable, Nonaccrual, Related Allowance	53	0
Commercial [Member] | Services [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual	17,170	25,598
Financing Receivable, Nonaccrual, No Allowance	13,686	20,810
Financing receivable, Nonaccrual, With Allowance	3,484	4,788
Financing Receivable, Nonaccrual, Related Allowance	2,584	2,574
Commercial [Member] | General business [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual	10,081	12,857
Financing Receivable, Nonaccrual, No Allowance	7,690	12,857
Financing receivable, Nonaccrual, With Allowance	2,391	0
Financing Receivable, Nonaccrual, Related Allowance	1,357	0
Commercial real estate [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual	14,262	27,246
Financing Receivable, Nonaccrual, No Allowance	6,186	13,645
Financing receivable, Nonaccrual, With Allowance	8,076	13,601
Financing Receivable, Nonaccrual, Related Allowance	2,349	3,389
Loans to individuals [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual	45,693	40,288
Financing Receivable, Nonaccrual, No Allowance	45,693	40,288
Financing receivable, Nonaccrual, With Allowance	0	0
Financing Receivable, Nonaccrual, Related Allowance	0	0
Loans to individuals [Member] | Residential mortgage [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual	31,574	32,228
Financing Receivable, Nonaccrual, No Allowance	31,574	32,228
Financing receivable, Nonaccrual, With Allowance	0	0
Financing Receivable, Nonaccrual, Related Allowance	0	0
Loans to individuals [Member] | Personal [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual	258	319
Financing Receivable, Nonaccrual, No Allowance	258	319
Financing receivable, Nonaccrual, With Allowance	0	0
Financing Receivable, Nonaccrual, Related Allowance	0	0
US Government Agency Insured Loans | Loans to individuals [Member] | Residential mortgage [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual	13,861	7,741
Financing Receivable, Nonaccrual, No Allowance	13,861	7,741
Financing receivable, Nonaccrual, With Allowance	0	0
Financing Receivable, Nonaccrual, Related Allowance	$ 0	$ 0