Disclosures about Fair Value of Financial Instruments - Estimated Fair Values of Financial Instruments (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Assets:
Cash and cash equivalents, carrying value	$ 518,032	$ 693,354
Cash and cash equivalents, fair value	518,032	693,354
Debt securities, available for sale	3,791,575	1,206,431
Equity securities	25,575	3,854
Loans held for sale	16,254	79,086
Total loans and leases receivable, net of allowance for credit losses on loans and leases, fair value	14,207,811	16,222,202
FHLB, Federal Reserve Bank and other restricted stock, carrying value	64,584	71,368
FHLB, Federal Reserve Bank and other restricted stock, fair value	64,584	71,368
Derivatives	27,295	54,223
Liabilities:
Deposits, carrying value	16,777,924	11,309,929
Deposits, fair value	16,777,236	11,312,494
FRB PPP Liquidity facility, carrying value	0	4,415,016
FRB PPP Liquidity Facility, fair value		4,415,016
Federal funds purchased, carrying value	75,000	250,000
Federal funds purchased, fair value	75,000	250,000
FHLB advances, carrying value	700,000	850,000
FHLB advances, fair value	700,000	852,442
Other borrowings, carrying value	223,086	124,037
Other borrowings, fair value	226,585	129,120
Subordinated debt, carrying value	181,673	181,394
Subordinated debt, fair value	204,782	193,119
Derivatives	26,544	98,164
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash and cash equivalents, fair value	518,032	693,354
Debt securities, available for sale	0	0
Equity securities		3,854
Loans held for sale	0	0
Total loans and leases receivable, net of allowance for credit losses on loans and leases, fair value	0	0
FHLB, Federal Reserve Bank and other restricted stock, fair value	0	0
Derivatives	0	0
Liabilities:
Deposits, fair value	16,270,586	10,657,998
FRB PPP Liquidity Facility, fair value		0
Federal funds purchased, fair value	75,000	250,000
FHLB advances, fair value	0	0
Other borrowings, fair value	0	0
Subordinated debt, fair value	0	0
Derivatives	0	0
Significant Other Observable Inputs (Level 2)
Assets:
Cash and cash equivalents, fair value	0	0
Debt securities, available for sale	3,648,690	1,206,431
Equity securities		0
Loans held for sale	15,747	78,443
Total loans and leases receivable, net of allowance for credit losses on loans and leases, fair value	2,284,325	3,616,432
FHLB, Federal Reserve Bank and other restricted stock, fair value	64,584	71,368
Derivatives	27,116	54,023
Liabilities:
Deposits, fair value	506,650	654,496
FRB PPP Liquidity Facility, fair value		4,415,016
Federal funds purchased, fair value	0	0
FHLB advances, fair value	700,000	852,442
Other borrowings, fair value	226,585	129,120
Subordinated debt, fair value	204,782	193,119
Derivatives	26,544	98,164
Significant Unobservable Inputs (Level 3)
Assets:
Cash and cash equivalents, fair value	0	0
Debt securities, available for sale	142,885	0
Equity securities		0
Loans held for sale	507	643
Total loans and leases receivable, net of allowance for credit losses on loans and leases, fair value	11,923,486	12,605,770
FHLB, Federal Reserve Bank and other restricted stock, fair value	0	0
Derivatives	179	200
Liabilities:
Deposits, fair value	0	0
FRB PPP Liquidity Facility, fair value		0
Federal funds purchased, fair value	0	0
FHLB advances, fair value	0	0
Other borrowings, fair value	0	0
Subordinated debt, fair value	0	0
Derivatives	$ 0	$ 0

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Amount of currency on hand as well as demand deposits with banks or financial institutions. 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. Excludes cash and cash equivalents within disposal group and discontinued operation.

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Amount excluding accrued interest, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Fair value portion of deposit liabilities held by the entity, including, but not limited to, foreign and domestic, interest and noninterest bearing, demand deposits, saving deposits, negotiable orders of withdrawal (NOW) and time deposits.

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Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI), classified as current.

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Fair value of subordinated debt obligations including, but not limited to, subordinated loan, subordinated bond, subordinated debenture or junior debt.

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Amount of short term borrowing where a bank borrows, at the federal funds rate, from another bank.

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Fair value portion of short term borrowing where a bank borrows, at the federal funds rate, from another bank.

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The carrying amount as of the balance sheet date for the aggregate of other miscellaneous borrowings owed by the reporting entity.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of subordinated debt (with initial maturities beyond one year or beyond the operating cycle if longer). Subordinated debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets.

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