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
	Mar. 31, 2022	Mar. 31, 2021	Jan. 01, 2022	Jan. 01, 2021
Financing Receivable, Impaired [Line Items]
Amortized Cost with Allowance	$ 827,842	$ 945,395
Amortized Cost without Allowance	1,306,389	1,011,711
Total	2,134,231	1,957,106
Amortized Cost			$ 2,060,083	$ 1,893,299
Interest Income Recognized	29,616	10,730
Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Impaired [Line Items]
Amortized Cost with Allowance	171,322	211,894
Amortized Cost without Allowance	103,824	83,175
Total	275,146	295,069
Amortized Cost			221,022	306,827
Interest Income Recognized	13,594	3,085
Commercial [Member]
Financing Receivable, Impaired [Line Items]
Amortized Cost with Allowance	222,771	337,036
Amortized Cost without Allowance	934,915	487,043
Total	1,157,686	824,079
Amortized Cost			1,069,280	775,894
Interest Income Recognized	6,131	1,658
Residential Builder and Developer [Member]
Financing Receivable, Impaired [Line Items]
Amortized Cost with Allowance	524	1,224
Amortized Cost without Allowance	2,392
Total	2,916	1,224
Amortized Cost			3,005	1,094
Interest Income Recognized	1,428	33
Other Commercial Construction [Member]
Financing Receivable, Impaired [Line Items]
Amortized Cost with Allowance	29,914	24,186
Amortized Cost without Allowance	20,941	102,039
Total	50,855	126,225
Amortized Cost			111,405	114,039
Interest Income Recognized	626	41
Residential [Member]
Financing Receivable, Impaired [Line Items]
Amortized Cost with Allowance	191,495	186,374
Amortized Cost without Allowance	150,176	199,134
Total	341,671	385,508
Amortized Cost			355,858	365,729
Interest Income Recognized	6,541	4,498
Residential Limited Documentation [Member]
Financing Receivable, Impaired [Line Items]
Amortized Cost with Allowance	80,590	84,342
Amortized Cost without Allowance	42,922	58,727
Total	123,512	143,069
Amortized Cost			122,888	147,170
Interest Income Recognized	196	79
Home Equity Lines and Loans [Member]
Financing Receivable, Impaired [Line Items]
Amortized Cost with Allowance	32,783	44,548
Amortized Cost without Allowance	38,706	34,640
Total	71,489	79,188
Amortized Cost			70,488	79,392
Interest Income Recognized	809	952
Recreational Finance [Member]
Financing Receivable, Impaired [Line Items]
Amortized Cost with Allowance	24,350	19,657
Amortized Cost without Allowance	7,196	7,561
Total	31,546	27,218
Amortized Cost			27,811	25,519
Interest Income Recognized	161	155
Automobile [Member]
Financing Receivable, Impaired [Line Items]
Amortized Cost with Allowance	30,129	33,270
Amortized Cost without Allowance	5,221	4,949
Total	35,350	38,219
Amortized Cost			34,037	39,404
Interest Income Recognized	38	49
Other [Member]
Financing Receivable, Impaired [Line Items]
Amortized Cost with Allowance	43,964	2,864
Amortized Cost without Allowance	96	34,443
Total	44,060	37,307
Amortized Cost			$ 44,289	$ 38,231
Interest Income Recognized	$ 92	$ 180