Fair Value Measurement and Fair Value of Financial Instruments- Carrying Values and Fair Values of Company's Financial Instruments (Detail) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Financial Assets:
Investment securities held to maturity, Carrying Value	$ 109,834	$ 123,975
Investment securities held to maturity, fair value	113,241	124,904
Federal Home Loan Bank and other membership bank stocks, Carrying Value	18,988	22,505
Federal Home Loan Bank and other membership bank stocks, Fair Value	18,988	22,505
Loans, net Carrying Value	5,698,316	5,097,820
Loans, net Fair Value	5,671,409	5,194,065
Financial Liabilities:
Certificates of deposit, Carrying value	1,128,506	870,804
Certificates of deposit, Fair Value	1,131,574	871,418
Other borrowings, Carrying value	155,715	165,816
Other borrowings, Fair Value	159,767	166,505
Subordinate debt	118,239	118,220
Subordinated debentures, Fair Value	114,222	117,992
Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial Assets:
Investment securities held to maturity, fair value	0	0
Federal Home Loan Bank and other membership bank stocks, Fair Value	0	0
Loans, net Fair Value	0	0
Financial Liabilities:
Certificates of deposit, Fair Value	0	0
Other borrowings, Fair Value	0	0
Subordinated debentures, Fair Value	0	0
Significant Other Observable Inputs (Level 2)
Financial Assets:
Investment securities held to maturity, fair value	110,741	121,503
Federal Home Loan Bank and other membership bank stocks, Fair Value	18,988	22,505
Loans, net Fair Value	0	0
Financial Liabilities:
Certificates of deposit, Fair Value	1,131,574	871,418
Other borrowings, Fair Value	159,767	166,505
Subordinated debentures, Fair Value	0	0
Significant Unobservable Inputs (Level 3)
Financial Assets:
Investment securities held to maturity, fair value	2,500	3,401
Federal Home Loan Bank and other membership bank stocks, Fair Value	0	0
Loans, net Fair Value	5,671,409	5,194,065
Financial Liabilities:
Certificates of deposit, Fair Value	0	0
Other borrowings, Fair Value	0	0
Subordinated debentures, Fair Value	$ 114,222	$ 117,992

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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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Federal Home Loan Bank (FHLB) stock represents an equity interest in a FHLB. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity).

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

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Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

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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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