PARENT COMPANY FINANCIAL INFORMATION - Statements of Condition (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Assets
Cash and cash equivalents	$ 420,020	$ 297,003
Investments available-for-sale (at fair value)	1,465,896	1,348,021
Equity securities	41,166	65,760
Goodwill	370,223	370,223	$ 347,149
Other assets	275,078	265,859
Total assets	12,590,726	12,798,429	8,629,002
Liabilities
Subordinated debt	172,712	227,088
Accrued expenses and other liabilities	132,518	146,085
Total liabilities	11,071,047	11,328,474
Stockholders’ Equity:
Common stock	45,119	47,057
Additional paid-in capital	751,072	846,922
Retained earnings	732,027	557,271
Accumulated other comprehensive income/ (loss)	(8,539)	18,705
Total stockholders' equity	1,519,679	1,469,955	$ 1,132,974	$ 1,067,903
Total liabilities and stockholders' equity	12,590,726	12,798,429
Parent Company
Assets
Cash and cash equivalents	69,038	63,943
Investments available-for-sale (at fair value)	0	9,925
Equity securities	568	568
Investment in subsidiary	1,620,432	1,589,483
Goodwill	1,292	1,292
Other assets	2,255	2,684
Total assets	1,693,585	1,667,895
Liabilities
Subordinated debt	172,712	196,454
Accrued expenses and other liabilities	1,194	1,486
Total liabilities	173,906	197,940
Stockholders’ Equity:
Common stock	45,119	47,057
Additional paid-in capital	751,072	846,922
Retained earnings	732,027	557,271
Accumulated other comprehensive income/ (loss)	(8,539)	18,705
Total stockholders' equity	1,519,679	1,469,955
Total liabilities and stockholders' equity	$ 1,693,585	$ 1,667,895