The amount of deposits assumed (as defined) which have been recognized as of the acquisition date.

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Amount of financing receivables after allowance for credit losses acquired during a business combination.

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Amount of assets acquired at the acquisition date.

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Amount of currency on hand as well as demand deposits with banks or financial institutions, acquired at the acquisition date. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Amount of investments in debt and equity securities, including, but not limited to, held-to-maturity, trading and available-for-sale expected to be converted to cash, sold or exchanged within one year or the normal operating cycle, if longer, acquired at the acquisition date.

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The amount of identifiable intangible assets recognized as of the acquisition date.

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Amount of liabilities assumed at the acquisition date.

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Amount recognized as of the acquisition date for the identifiable assets acquired in excess of (less than) the aggregate liabilities assumed.

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Amount of other liabilities due after one year or the normal operating cycle, if longer, assumed at the acquisition date.

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Amount of other assets expected to be realized or consumed after one year or the normal operating cycle, if longer, acquired at the acquisition date.

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The amount of property, plant, and equipment recognized as of the acquisition date.

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

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BUSINESS COMBINATION - Estimated Fair Value of Net Assets Acquired (Detail) - USD ($) $ in Thousands		9 Months Ended
	Sep. 01, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Total purchase price consideration (cash)		$ 0	$ 1,277,626
Fair value of assets acquired:
Total assets and identifiable intangible assets acquired		0	5,562,152
Fair value of liabilities assumed:
Total liabilities assumed		0	$ 4,290,829
Goodwill		38,611		$ 38,632	$ 28,098
BSPR
Fair value of liabilities assumed:
Goodwill		$ 10,500
BSPR \| Measurment Period Adjustments [Member]
Business Acquisition [Line Items]
Total purchase price consideration (cash)	$ 3,382
Fair value of assets acquired:
Cash and cash equivalents	0
Investment securities	0
Loans, net	(216)
Premises and equipment, net	0
Intangibles	448
Other assets	(195)
Total assets and identifiable intangible assets acquired	37
Fair value of liabilities assumed:
Deposits	0
Other liabilities	865
Total liabilities assumed	865
Fair value of net assets and identifiable intangible assets	(828)
Goodwill	4,210
BSPR \| Measurment Period Adjustments [Member] \| Residential Portfolio Segment [Member]
Fair value of assets acquired:
Loans, net	540
BSPR \| Measurment Period Adjustments [Member] \| Commercial Portfolio Segment [Member] \| Mortgage Receivable [Member]
Fair value of assets acquired:
Loans, net	122
BSPR \| Measurment Period Adjustments [Member] \| Commercial Portfolio Segment [Member] \| Commercial And Industrial Sector [Member]
Fair value of assets acquired:
Loans, net	(390)
BSPR \| Measurment Period Adjustments [Member] \| Consumer Portfolio Segment [Member]
Fair value of assets acquired:
Loans, net	(488)
BSPR \| Fair Value as Originally Recorded
Business Acquisition [Line Items]
Total purchase price consideration (cash)	1,277,626
Fair value of assets acquired:
Cash and cash equivalents	1,684,252
Investment securities	1,167,225
Loans, net	2,514,916
Premises and equipment, net	12,499
Intangibles	39,232
Other assets	144,008
Total assets and identifiable intangible assets acquired	5,562,132
Fair value of liabilities assumed:
Deposits	4,194,940
Other liabilities	95,869
Total liabilities assumed	4,290,809
Fair value of net assets and identifiable intangible assets	1,271,323
Goodwill	6,303
BSPR \| Fair Value as Originally Recorded \| Residential Portfolio Segment [Member]
Fair value of assets acquired:
Loans, net	807,637
BSPR \| Fair Value as Originally Recorded \| Commercial Portfolio Segment [Member] \| Mortgage Receivable [Member]
Fair value of assets acquired:
Loans, net	740,919
BSPR \| Fair Value as Originally Recorded \| Commercial Portfolio Segment [Member] \| Commercial And Industrial Sector [Member]
Fair value of assets acquired:
Loans, net	752,154
BSPR \| Fair Value as Originally Recorded \| Consumer Portfolio Segment [Member]
Fair value of assets acquired:
Loans, net	214,206
BSPR \| Fair Value as Remeasured
Business Acquisition [Line Items]
Total purchase price consideration (cash)	1,281,008
Fair value of assets acquired:
Cash and cash equivalents	1,684,252
Investment securities	1,167,225
Loans, net	2,514,700
Premises and equipment, net	12,499
Intangibles	39,680
Other assets	143,813
Total assets and identifiable intangible assets acquired	5,562,169
Fair value of liabilities assumed:
Deposits	4,194,940
Other liabilities	96,734
Total liabilities assumed	4,291,674
Fair value of net assets and identifiable intangible assets	1,270,495
Goodwill	10,513
BSPR \| Fair Value as Remeasured \| Residential Portfolio Segment [Member]
Fair value of assets acquired:
Loans, net	808,177
BSPR \| Fair Value as Remeasured \| Commercial Portfolio Segment [Member] \| Mortgage Receivable [Member]
Fair value of assets acquired:
Loans, net	741,041
BSPR \| Fair Value as Remeasured \| Commercial Portfolio Segment [Member] \| Commercial And Industrial Sector [Member]
Fair value of assets acquired:
Loans, net	751,764
BSPR \| Fair Value as Remeasured \| Consumer Portfolio Segment [Member]
Fair value of assets acquired:
Loans, net	$ 213,718