Fair Value - Fair Value Measurements of Other Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Assets
Cash and due from banks	$ 196,364	$ 214,894
Interest-bearing deposits in other banks	920,880	84,327
Securities held-to-maturity	12,071	21,997
FHLB and FRB stock	117,420	115,409
Loans	14,512,215	12,732,308
Investment in BOLI	301,101	296,351
Liabilities
Deposits	16,012,464	13,251,278
Borrowed funds	1,546,414	1,658,758
Subordinated debt	234,768	233,948
Level 1 \| Carrying Amount
Assets
Cash and due from banks	196,364	214,894
Level 1 \| Fair Value
Assets
Cash and due from banks	196,364	214,894
Level 2 \| Carrying Amount
Assets
Interest-bearing deposits in other banks	920,880	84,327
Securities held-to-maturity	12,071	21,997
FHLB and FRB stock	117,420	115,409
Liabilities
Deposits	16,012,464	13,251,278
Borrowed funds	1,546,414	1,658,758
Subordinated debt	234,768	233,948
Accrued interest payable	4,826	10,502
Level 2 \| Fair Value
Assets
Interest-bearing deposits in other banks	920,880	84,327
Securities held-to-maturity	11,686	21,234
FHLB and FRB stock	117,420	115,409
Liabilities
Deposits	16,007,133	13,247,871
Borrowed funds	1,546,414	1,658,758
Subordinated debt	281,843	277,203
Accrued interest payable	4,826	10,502
Level 3 \| Carrying Amount
Assets
Loans	14,512,215	12,733,200
Investment in BOLI	301,101	296,351
Accrued interest receivable	68,390	59,716
Level 3 \| Fair Value
Assets
Loans	14,614,029	12,535,848
Investment in BOLI	301,101	296,351
Accrued interest receivable	$ 68,390	$ 59,716

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The carrying amount of a life insurance policy on an officer, executive or employee for which the reporting entity (a bank) is entitled to proceeds from the policy upon death of the insured or surrender of the insurance policy.

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For banks and other depository institutions: Includes cash on hand (currency and coin), cash items in process of collection, noninterest bearing deposits due from other financial institutions (including corporate credit unions), and noninterest bearing balances with the Federal Reserve Banks, Federal Home Loan Banks and central banks.

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The aggregate of all deposit liabilities held by the entity, including foreign and domestic, interest and noninterest bearing; may include demand deposits, saving deposits, Negotiable Order of Withdrawal (NOW) and time deposits among others.

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Amount of Federal Home Loan Bank (FHLB) and Federal Reserve Bank stock.

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Amount of investment in debt security measured at amortized cost (held-to-maturity).

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For banks and other depository institutions (including Federal Reserve Banks, if applicable): Interest-bearing deposits in other financial institutions for relatively short periods of time including, for example, certificates of deposits, which are presented separately from cash on the balance sheet.

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Amount of interest payable on debt, including, but not limited to, trade payables.

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Carrying amount as of the balance sheet date of interest earned but not received. Also called accrued interest or accrued interest receivable.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount, after allowance for credit loss, of financing receivable. Excludes financing receivable covered under loss sharing agreement.

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Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

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