Loans and Leases and the Allowance for Credit Losses - Loan and Leases Considered Nonaccrual and Interest Income Recognized on Loans (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Jun. 30, 2023	Jan. 01, 2023	Jun. 30, 2022	Jan. 01, 2022
Financing Receivable, Impaired [Line Items]
Amortized Cost with Allowance	$ 1,038,213	$ 1,005,944	$ 1,038,213	$ 1,005,944
Amortized Cost without Allowance	1,303,725	1,423,382	1,303,725	1,423,382
Total	2,341,938	2,429,326	2,341,938	2,429,326
Amortized Cost					$ 2,435,581	$ 2,438,435	$ 2,633,005	$ 2,060,083
Interest Income Recognized	22,107	21,031	51,644	66,462
Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Impaired [Line Items]
Amortized Cost with Allowance	324,774	207,841	324,774	207,841
Amortized Cost without Allowance	160,646	160,325	160,646	160,325
Total	485,420	368,166	485,420	368,166
Amortized Cost					416,022	347,204	442,496	221,022
Interest Income Recognized	3,726	4,708	7,914	20,423
Commercial [Member]
Financing Receivable, Impaired [Line Items]
Amortized Cost with Allowance	458,720	394,502	458,720	394,502
Amortized Cost without Allowance	777,367	1,011,698	777,367	1,011,698
Total	1,236,087	1,406,200	1,236,087	1,406,200
Amortized Cost					1,383,190	1,396,662	1,476,658	1,069,280
Interest Income Recognized	12,446	7,059	22,379	14,944
Residential Builder and Developer [Member]
Financing Receivable, Impaired [Line Items]
Amortized Cost with Allowance	3,353	1,930	3,353	1,930
Total	3,353	1,930	3,353	1,930
Amortized Cost					1,193	1,229	518	3,005
Interest Income Recognized			396	1,687
Other Commercial Construction [Member]
Financing Receivable, Impaired [Line Items]
Amortized Cost with Allowance	4,080	25,235	4,080	25,235
Amortized Cost without Allowance	131,924	40,952	131,924	40,952
Total	136,004	66,187	136,004	66,187
Amortized Cost					146,024	124,937	73,046	111,405
Interest Income Recognized	249	22	1,974	3,398
Residential [Member]
Financing Receivable, Impaired [Line Items]
Amortized Cost with Allowance	90,879	160,704	90,879	160,704
Amortized Cost without Allowance	149,874	124,691	149,874	124,691
Total	240,753	285,395	240,753	285,395
Amortized Cost					238,509	272,090	331,376	355,858
Interest Income Recognized	3,480	8,059	12,247	21,397
Residential Limited Documentation [Member]
Financing Receivable, Impaired [Line Items]
Amortized Cost with Allowance	21,634	61,297	21,634	61,297
Amortized Cost without Allowance	40,616	34,085	40,616	34,085
Total	62,250	95,382	62,250	95,382
Amortized Cost					66,614	77,814	112,608	122,888
Interest Income Recognized	426	229	686	456
Home Equity Lines and Loans [Member]
Financing Receivable, Impaired [Line Items]
Amortized Cost with Allowance	48,737	38,324	48,737	38,324
Amortized Cost without Allowance	29,579	39,884	29,579	39,884
Total	78,316	78,208	78,316	78,208
Amortized Cost					77,090	84,788	79,445	70,488
Interest Income Recognized	1,493	669	5,172	3,291
Recreational Finance [Member]
Financing Receivable, Impaired [Line Items]
Amortized Cost with Allowance	20,955	31,295	20,955	31,295
Amortized Cost without Allowance	9,569	7,423	9,569	7,423
Total	30,524	38,718	30,524	38,718
Amortized Cost					32,286	44,630	33,414	27,811
Interest Income Recognized	185	166	536	488
Automobile [Member]
Financing Receivable, Impaired [Line Items]
Amortized Cost with Allowance	11,981	36,075	11,981	36,075
Amortized Cost without Allowance	3,978	4,243	3,978	4,243
Total	15,959	40,318	15,959	40,318
Amortized Cost					21,791	39,584	36,266	34,037
Interest Income Recognized	36	35	107	110
Other [Member]
Financing Receivable, Impaired [Line Items]
Amortized Cost with Allowance	53,100	48,741	53,100	48,741
Amortized Cost without Allowance	172	81	172	81
Total	53,272	48,822	53,272	48,822
Amortized Cost					$ 52,862	$ 49,497	$ 47,178	$ 44,289
Interest Income Recognized	$ 66	$ 84	$ 233	$ 268