CREDIT QUALITY ASSESSMENT - Information about Credit Quality Indicator by Year of Origination (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	$ 3,023,908	$ 3,305,720
Year one	1,626,031	1,774,275
Year two	1,316,007	1,179,845
Year three	826,781	1,016,641
Year four	702,719	866,898
Prior	1,376,294	1,242,626
Revolving Loans	1,095,351	1,014,504
Total	9,967,091	10,400,509
Current period gross charge-offs, total	12,313	1,819	$ 2,668
Commercial investor real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	1,394,986	922,059
Year one	749,082	767,459
Year two	625,715	466,934
Year three	366,804	470,150
Year four	340,595	470,019
Prior	644,925	504,568
Revolving Loans	19,239	33,531
Total	4,141,346	3,634,720
Current period gross charge-offs, current year	0	0
Current period gross charge-offs, year one	0	388
Current period gross charge-offs, year two	0	0
Current period gross charge-offs, year three	903	0
Current period gross charge-offs, year four	3,975	0
Current period gross charge-offs, prior	924	23
Current period gross charge-offs, revolving loans	0	0
Current period gross charge-offs, total	5,802	411
Commercial investor real estate | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	1,391,969	910,426
Year one	748,236	763,214
Year two	616,761	448,406
Year three	357,640	448,698
Year four	328,327	469,077
Prior	633,913	498,384
Revolving Loans	19,239	33,531
Total	4,096,085	3,571,736
Commercial investor real estate | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	2,210	11,044
Year one	510	0
Year two	4,646	4,879
Year three	596	833
Year four	2,204	269
Prior	10,438	27
Revolving Loans	0	0
Total	20,604	17,052
Commercial investor real estate | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	807	589
Year one	336	4,245
Year two	4,308	13,649
Year three	8,568	20,619
Year four	10,064	673
Prior	574	6,157
Revolving Loans	0	0
Total	24,657	45,932
Commercial investor real estate | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	0	0
Year one	0	0
Year two	0	0
Year three	0	0
Year four	0	0
Prior	0	0
Revolving Loans	0	0
Total	0	0
Commercial owner-occupied real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	362,293	289,210
Year one	257,626	389,393
Year two	327,764	239,670
Year three	189,716	197,841
Year four	177,164	205,278
Prior	375,169	319,160
Revolving Loans	1,149	1,664
Total	1,690,881	1,642,216
Current period gross charge-offs, current year	0	0
Current period gross charge-offs, year one	0	0
Current period gross charge-offs, year two	0	0
Current period gross charge-offs, year three	136	0
Current period gross charge-offs, year four	0	0
Current period gross charge-offs, prior	0	0
Current period gross charge-offs, revolving loans	0	0
Current period gross charge-offs, total	136	0
Commercial owner-occupied real estate | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	360,169	285,310
Year one	254,350	385,058
Year two	319,348	234,578
Year three	178,416	192,634
Year four	172,354	204,925
Prior	363,685	306,840
Revolving Loans	1,149	1,664
Total	1,649,471	1,611,009
Commercial owner-occupied real estate | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	156	2,290
Year one	1,476	0
Year two	4,388	3,027
Year three	9,035	4,742
Year four	4,456	134
Prior	9,106	4,079
Revolving Loans	0	0
Total	28,617	14,272
Commercial owner-occupied real estate | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	1,968	1,610
Year one	1,800	4,335
Year two	4,028	2,065
Year three	2,265	465
Year four	354	219
Prior	2,378	8,009
Revolving Loans	0	0
Total	12,793	16,703
Commercial owner-occupied real estate | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	0	0
Year one	0	0
Year two	0	0
Year three	0	0
Year four	0	0
Prior	0	232
Revolving Loans	0	0
Total	0	232
Commercial AD&C
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	457,444	488,781
Year one	226,332	262,428
Year two	148,561	149,703
Year three	87,934	64,008
Year four	13,938	2,932
Prior	0	2,357
Revolving Loans	153,885	80,764
Total	1,088,094	1,050,973
Current period gross charge-offs, current year	0	0
Current period gross charge-offs, year one	0	0
Current period gross charge-offs, year two	0	0
Current period gross charge-offs, year three	0	0
Current period gross charge-offs, year four	2,007	0
Current period gross charge-offs, prior	0	0
Current period gross charge-offs, revolving loans	0	0
Current period gross charge-offs, total	2,007	0
Commercial AD&C | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	454,207	485,631
Year one	226,332	261,537
Year two	148,260	149,703
Year three	87,934	50,192
Year four	13,938	89
Prior	0	2,357
Revolving Loans	152,896	80,764
Total	1,083,567	1,030,273
Commercial AD&C | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	2,888	1,711
Year one	0	0
Year two	0	0
Year three	0	0
Year four	0	0
Prior	0	0
Revolving Loans	989	0
Total	3,877	1,711
Commercial AD&C | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	349	1,439
Year one	0	891
Year two	301	0
Year three	0	13,816
Year four	0	2,843
Prior	0	0
Revolving Loans	0	0
Total	650	18,989
Commercial AD&C | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	0	0
Year one	0	0
Year two	0	0
Year three	0	0
Year four	0	0
Prior	0	0
Revolving Loans	0	0
Total	0	0
Residential mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	259,638	236,909
Year one	175,065	85,106
Year two	54,245	158,382
Year three	76,471	188,970
Year four	110,951	143,557
Prior	261,200	292,255
Revolving Loans	0	0
Total	937,570	1,105,179
Current period gross charge-offs, current year	0	0
Current period gross charge-offs, year one	0	0
Current period gross charge-offs, year two	0	0
Current period gross charge-offs, year three	0	0
Current period gross charge-offs, year four	0	11
Current period gross charge-offs, prior	0	473
Current period gross charge-offs, revolving loans	0	0
Current period gross charge-offs, total	0	484
Residential mortgage | 660-850
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	246,612	229,033
Year one	165,623	74,054
Year two	46,925	138,824
Year three	65,865	172,493
Year four	102,628	129,701
Prior	223,420	251,065
Revolving Loans	0	0
Total	851,073	995,170
Residential mortgage | 600-659
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	11,102	4,824
Year one	3,285	7,706
Year two	3,583	10,763
Year three	4,255	11,719
Year four	4,645	8,173
Prior	20,052	21,424
Revolving Loans	0	0
Total	46,922	64,609
Residential mortgage | 540-599
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	1,472	350
Year one	1,864	1,238
Year two	2,162	5,219
Year three	4,522	2,608
Year four	1,599	4,791
Prior	8,201	10,167
Revolving Loans	0	0
Total	19,820	24,373
Residential mortgage | less than 540
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	452	2,702
Year one	4,293	2,108
Year two	1,575	3,576
Year three	1,829	2,150
Year four	2,079	892
Prior	9,527	9,599
Revolving Loans	0	0
Total	19,755	21,027
Residential construction
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	138,002	115,201
Year one	45,890	47,836
Year two	8,713	14,543
Year three	2,078	2,805
Year four	1,347	2,062
Prior	1,622	0
Revolving Loans	0	172
Total	197,652	182,619
Current period gross charge-offs, current year	0	0
Current period gross charge-offs, year one	0	0
Current period gross charge-offs, year two	0	0
Current period gross charge-offs, year three	0	0
Current period gross charge-offs, year four	0	0
Current period gross charge-offs, prior	0	0
Current period gross charge-offs, revolving loans	0	0
Current period gross charge-offs, total	0	0
Residential construction | 660-850
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	134,335	112,604
Year one	45,890	44,647
Year two	8,063	14,543
Year three	2,078	2,805
Year four	1,347	1,693
Prior	1,160	0
Revolving Loans	0	172
Total	192,873	176,464
Residential construction | 600-659
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	1,922	1,743
Year one	0	3,189
Year two	650	0
Year three	0	0
Year four	0	0
Prior	0	0
Revolving Loans	0	0
Total	2,572	4,932
Residential construction | 540-599
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	0	0
Year one	0	0
Year two	0	0
Year three	0	0
Year four	0	369
Prior	462	0
Revolving Loans	0	0
Total	462	369
Residential construction | less than 540
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	1,745	854
Year one	0	0
Year two	0	0
Year three	0	0
Year four	0	0
Prior	0	0
Revolving Loans	0	0
Total	1,745	854
Commercial Business
Financing Receivable, Credit Quality Indicator [Line Items]
Total	8,402,155	8,595,457
Commercial Business | Commercial business
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	407,868	1,249,771
Year one	170,454	215,623
Year two	146,708	144,348
Year three	99,298	89,205
Year four	56,459	38,836
Prior	56,406	87,689
Revolving Loans	544,641	442,076
Total	1,481,834	2,267,548
Current period gross charge-offs, current year	0	0
Current period gross charge-offs, year one	0	0
Current period gross charge-offs, year two	88	23
Current period gross charge-offs, year three	1,674	160
Current period gross charge-offs, year four	46	103
Current period gross charge-offs, prior	2,236	205
Current period gross charge-offs, revolving loans	25	0
Current period gross charge-offs, total	4,069	491
Commercial Business | Commercial business | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	403,871	1,244,822
Year one	165,194	208,682
Year two	137,069	138,861
Year three	96,800	86,830
Year four	55,100	34,498
Prior	53,764	81,760
Revolving Loans	533,893	433,016
Total	1,445,691	2,228,469
Commercial Business | Commercial business | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	220	1,929
Year one	1,998	1,382
Year two	7,030	1,119
Year three	1,701	708
Year four	548	309
Prior	577	621
Revolving Loans	9,212	4,319
Total	21,286	10,387
Commercial Business | Commercial business | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	3,777	2,914
Year one	3,262	4,564
Year two	2,609	3,519
Year three	797	1,631
Year four	811	2,745
Prior	2,065	3,456
Revolving Loans	1,536	1,829
Total	14,857	20,658
Commercial Business | Commercial business | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	0	106
Year one	0	995
Year two	0	849
Year three	0	36
Year four	0	1,284
Prior	0	1,852
Revolving Loans	0	2,912
Total	0	8,034
Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	3,677	3,789
Year one	1,582	6,430
Year two	4,301	6,265
Year three	4,480	3,662
Year four	2,265	4,214
Prior	36,972	36,597
Revolving Loans	376,437	456,297
Total	429,714	517,254
Current period gross charge-offs, current year	0	0
Current period gross charge-offs, year one	0	13
Current period gross charge-offs, year two	7	123
Current period gross charge-offs, year three	2	8
Current period gross charge-offs, year four	0	1
Current period gross charge-offs, prior	106	140
Current period gross charge-offs, revolving loans	184	148
Current period gross charge-offs, total	299	433
Consumer | 660-850
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	3,179	2,575
Year one	1,393	4,609
Year two	3,130	5,112
Year three	3,060	2,110
Year four	1,648	2,614
Prior	26,156	24,444
Revolving Loans	350,466	417,737
Total	389,032	459,201
Consumer | 600-659
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	352	374
Year one	123	445
Year two	324	334
Year three	716	428
Year four	430	467
Prior	4,906	5,401
Revolving Loans	14,119	21,052
Total	20,970	28,501
Consumer | 540-599
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	58	89
Year one	8	1,216
Year two	311	294
Year three	160	339
Year four	89	601
Prior	2,809	3,926
Revolving Loans	4,926	6,153
Total	8,361	12,618
Consumer | less than 540
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	88	751
Year one	58	160
Year two	536	525
Year three	544	785
Year four	98	532
Prior	3,101	2,826
Revolving Loans	6,926	11,355
Total	$ 11,351	$ 16,934