CREDIT QUALITY ASSESSMENT - Information about Credit Quality Indicator by Year of Origination (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	$ 789,415		$ 3,023,908
Year one	2,891,943		1,626,031
Year two	1,507,919		1,316,007
Year three	1,211,931		826,781
Year four	758,402		702,719
Prior	1,938,967		1,376,294
Revolving Loans	1,045,751		1,095,351
Total	10,144,328		9,967,091
Current period gross charge-offs, total	306	$ 743	12,313
Commercial investor real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	384,736		1,394,986
Year one	1,354,704		749,082
Year two	730,346		625,715
Year three	603,908		366,804
Year four	355,329		340,595
Prior	944,565		644,925
Revolving Loans	14,687		19,239
Total	4,388,275		4,141,346
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		903
Current period gross charge-offs, year four	0		3,975
Current period gross charge-offs, prior	0		924
Current period gross charge-offs, revolving	0		0
Current period gross charge-offs, total	0		5,802
Commercial investor real estate | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	384,736		1,391,969
Year one	1,349,176		748,236
Year two	729,504		616,761
Year three	601,556		357,640
Year four	346,334		328,327
Prior	927,482		633,913
Revolving Loans	14,687		19,239
Total	4,353,475		4,096,085
Commercial investor real estate | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	0		2,210
Year one	4,736		510
Year two	506		4,646
Year three	96		596
Year four	589		2,204
Prior	7,019		10,438
Revolving Loans	0		0
Total	12,946		20,604
Commercial investor real estate | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	0		807
Year one	792		336
Year two	336		4,308
Year three	2,256		8,568
Year four	8,406		10,064
Prior	10,064		574
Revolving Loans	0		0
Total	21,854		24,657
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	121,412		362,293
Year one	353,336		257,626
Year two	242,104		327,764
Year three	310,783		189,716
Year four	171,166		177,164
Prior	492,553		375,169
Revolving Loans	899		1,149
Total	1,692,253		1,690,881
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		136
Current period gross charge-offs, year four	0		0
Current period gross charge-offs, prior	0		0
Current period gross charge-offs, revolving	0		0
Current period gross charge-offs, total	0		136
Commercial owner-occupied real estate | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	120,495		360,169
Year one	351,408		254,350
Year two	240,259		319,348
Year three	302,230		178,416
Year four	166,269		172,354
Prior	480,409		363,685
Revolving Loans	899		1,149
Total	1,661,969		1,649,471
Commercial owner-occupied real estate | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	917		156
Year one	0		1,476
Year two	932		4,388
Year three	470		9,035
Year four	2,643		4,456
Prior	9,554		9,106
Revolving Loans	0		0
Total	14,516		28,617
Commercial owner-occupied real estate | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	0		1,968
Year one	1,928		1,800
Year two	913		4,028
Year three	8,083		2,265
Year four	2,254		354
Prior	2,590		2,378
Revolving Loans	0		0
Total	15,768		12,793
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		0
Revolving Loans	0		0
Total	0		0
Commercial AD&C
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	87,554		457,444
Year one	478,834		226,332
Year two	183,536		148,561
Year three	96,961		87,934
Year four	62,776		13,938
Prior	13,887		0
Revolving Loans	165,783		153,885
Total	1,089,331		1,088,094
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		2,007
Current period gross charge-offs, prior	0		0
Current period gross charge-offs, revolving	0		0
Current period gross charge-offs, total	0		2,007
Commercial AD&C | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	86,642		454,207
Year one	475,981		226,332
Year two	183,536		148,260
Year three	96,660		87,934
Year four	62,776		13,938
Prior	13,887		0
Revolving Loans	164,794		152,896
Total	1,084,276		1,083,567
Commercial AD&C | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	912		2,888
Year one	2,073		0
Year two	0		0
Year three	0		0
Year four	0		0
Prior	0		0
Revolving Loans	989		989
Total	3,974		3,877
Commercial AD&C | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	0		349
Year one	780		0
Year two	0		301
Year three	301		0
Year four	0		0
Prior	0		0
Revolving Loans	0		0
Total	1,081		650
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	96,795		259,638
Year one	259,965		175,065
Year two	173,628		54,245
Year three	52,787		76,471
Year four	69,744		110,951
Prior	347,778		261,200
Revolving Loans	0		0
Total	1,000,697		937,570
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	132		0
Current period gross charge-offs, revolving	0		0
Current period gross charge-offs, total	132		0
Residential mortgage | 660-850
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	93,493		246,612
Year one	251,932		165,623
Year two	166,024		46,925
Year three	45,753		65,865
Year four	58,950		102,628
Prior	306,194		223,420
Revolving Loans	0		0
Total	922,346		851,073
Residential mortgage | 600-659
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	206		11,102
Year one	4,497		3,285
Year two	2,977		3,583
Year three	4,361		4,255
Year four	4,812		4,645
Prior	23,340		20,052
Revolving Loans	0		0
Total	40,193		46,922
Residential mortgage | 540-599
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	242		1,472
Year one	1,982		1,864
Year two	1,141		2,162
Year three	1,439		4,522
Year four	4,736		1,599
Prior	7,966		8,201
Revolving Loans	0		0
Total	17,506		19,820
Residential mortgage | less than 540
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	2,854		452
Year one	1,554		4,293
Year two	3,486		1,575
Year three	1,234		1,829
Year four	1,246		2,079
Prior	10,278		9,527
Revolving Loans	0		0
Total	20,652		19,755
Residential construction
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	21,223		138,002
Year one	137,853		45,890
Year two	36,510		8,713
Year three	6,167		2,078
Year four	1,346		1,347
Prior	1,160		1,622
Revolving Loans	0		0
Total	204,259		197,652
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	0		0
Current period gross charge-offs, total	0		0
Residential construction | 660-850
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	20,890		134,335
Year one	134,821		45,890
Year two	36,510		8,063
Year three	6,167		2,078
Year four	1,346		1,347
Prior	1,160		1,160
Revolving Loans	0		0
Total	200,894		192,873
Residential construction | 600-659
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	0		1,922
Year one	1,110		0
Year two	0		650
Year three	0		0
Year four	0		0
Prior	0		0
Revolving Loans	0		0
Total	1,110		2,572
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		0
Prior	0		462
Revolving Loans	0		0
Total	0		462
Residential construction | less than 540
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	333		1,745
Year one	1,922		0
Year two	0		0
Year three	0		0
Year four	0		0
Prior	0		0
Revolving Loans	0		0
Total	2,255		1,745
Commercial Business
Financing Receivable, Credit Quality Indicator [Line Items]
Total	8,519,461		8,402,155
Commercial Business | Commercial business
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	76,747		407,868
Year one	303,746		170,454
Year two	140,453		146,708
Year three	138,089		99,298
Year four	94,234		56,459
Prior	101,159		56,406
Revolving Loans	495,174		544,641
Total	1,349,602		1,481,834
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		88
Current period gross charge-offs, year three	0		1,674
Current period gross charge-offs, year four	118		46
Current period gross charge-offs, prior	0		2,236
Current period gross charge-offs, revolving	0		25
Current period gross charge-offs, total	118		4,069
Commercial Business | Commercial business | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	76,700		403,871
Year one	299,668		165,194
Year two	135,911		137,069
Year three	128,342		96,800
Year four	91,993		55,100
Prior	97,581		53,764
Revolving Loans	485,438		533,893
Total	1,315,633		1,445,691
Commercial Business | Commercial business | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	32		220
Year one	408		1,998
Year two	1,840		7,030
Year three	6,727		1,701
Year four	1,563		548
Prior	747		577
Revolving Loans	8,273		9,212
Total	19,590		21,286
Commercial Business | Commercial business | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	15		3,777
Year one	3,670		3,262
Year two	2,702		2,609
Year three	3,020		797
Year four	678		811
Prior	2,831		2,065
Revolving Loans	1,463		1,536
Total	14,379		14,857
Commercial Business | Commercial business | 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
Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	948		3,677
Year one	3,505		1,582
Year two	1,342		4,301
Year three	3,236		4,480
Year four	3,807		2,265
Prior	37,865		36,972
Revolving Loans	369,208		376,437
Total	419,911		429,714
Current period gross charge-offs, current year	0		0
Current period gross charge-offs, year one	5		0
Current period gross charge-offs, year two	0		7
Current period gross charge-offs, year three	0		2
Current period gross charge-offs, year four	0		0
Current period gross charge-offs, prior	0		106
Current period gross charge-offs, revolving	51		184
Current period gross charge-offs, total	56		299
Consumer | 660-850
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	789		3,179
Year one	2,825		1,393
Year two	1,226		3,130
Year three	2,317		3,060
Year four	2,541		1,648
Prior	26,724		26,156
Revolving Loans	343,402		350,466
Total	379,824		389,032
Consumer | 600-659
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	106		352
Year one	392		123
Year two	58		324
Year three	109		716
Year four	418		430
Prior	5,189		4,906
Revolving Loans	14,630		14,119
Total	20,902		20,970
Consumer | 540-599
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	2		58
Year one	207		8
Year two	2		311
Year three	641		160
Year four	232		89
Prior	2,941		2,809
Revolving Loans	4,457		4,926
Total	8,482		8,361
Consumer | less than 540
Financing Receivable, Credit Quality Indicator [Line Items]
Current year	51		88
Year one	81		58
Year two	56		536
Year three	169		544
Year four	616		98
Prior	3,011		3,101
Revolving Loans	6,719		6,926
Total	$ 10,703		$ 11,351