Loans Receivable, Net - Allowance for Loan Loses and Recorded Investment in Loans by Portfolio Segment and Based on Impairment Method Excluding PCI Loans (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year	$ 16,577	$ 15,721	$ 15,183
Provision (benefit) charged to operations	1,636	3,490
Charge-offs	(2,804)	(3,841)	(5,384)
Recoveries	1,443	1,207	1,477
Balance at end of year	16,852	16,577	15,721
Ending allowance balance attributed to loans:
Individually evaluated for impairment	476	0
Collectively evaluated for impairment	16,376	16,577
Total ending allowance balance	16,852	16,577
Loans:
Loans individually evaluated for impairment	26,510	29,797
Loans collectively evaluated for impairment	6,174,877	5,550,015
Total	6,201,387	5,579,812
Commercial and industrial
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year	1,609	1,801
Provision (benefit) charged to operations	(311)	(66)
Charge-offs	0	(230)
Recoveries	160	104
Balance at end of year	1,458	1,609	1,801
Ending allowance balance attributed to loans:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	1,458	1,609
Total ending allowance balance	1,458	1,609
Loans:
Loans individually evaluated for impairment	243	1,626
Loans collectively evaluated for impairment	395,848	303,368
Total	396,091	304,994
Commercial real estate – owner occupied
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year	2,277	3,175
Provision (benefit) charged to operations	947	(783)
Charge-offs	(663)	(314)
Recoveries	332	199
Balance at end of year	2,893	2,277	3,175
Ending allowance balance attributed to loans:
Individually evaluated for impairment	474	0
Collectively evaluated for impairment	2,419	2,277
Total ending allowance balance	2,893	2,277
Loans:
Loans individually evaluated for impairment	6,163	5,395
Loans collectively evaluated for impairment	785,778	734,980
Total	791,941	740,375
Commercial real estate - investor
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year	8,770	7,952
Provision (benefit) charged to operations	638	2,550
Charge-offs	(236)	(1,939)
Recoveries	711	207
Balance at end of year	9,883	8,770	7,952
Ending allowance balance attributed to loans:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	9,883	8,770
Total ending allowance balance	9,883	8,770
Loans:
Loans individually evaluated for impairment	5,584	9,738
Loans collectively evaluated for impairment	2,279,114	2,005,472
Total	2,284,698	2,015,210
Residential real estate
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year	2,413	1,804
Provision (benefit) charged to operations	792	1,056
Charge-offs	(1,299)	(1,021)
Recoveries	96	574
Balance at end of year	2,002	2,413	1,804
Ending allowance balance attributed to loans:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	2,002	2,413
Total ending allowance balance	2,002	2,413
Loans:
Loans individually evaluated for impairment	11,009	10,064
Loans collectively evaluated for impairment	2,309,812	2,034,222
Total	2,320,821	2,044,286
Consumer
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year	486	614
Provision (benefit) charged to operations	567	86
Charge-offs	(606)	(337)
Recoveries	144	123
Balance at end of year	591	486	614
Ending allowance balance attributed to loans:
Individually evaluated for impairment	2	0
Collectively evaluated for impairment	589	486
Total ending allowance balance	591	486
Loans:
Loans individually evaluated for impairment	3,511	2,974
Loans collectively evaluated for impairment	404,325	471,973
Total	407,836	474,947
Unallocated
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year	1,022	375
Provision (benefit) charged to operations	(997)	647
Charge-offs	0	0
Recoveries	0	0
Balance at end of year	25	1,022	$ 375
Ending allowance balance attributed to loans:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	25	1,022
Total ending allowance balance	25	1,022
Loans:
Loans individually evaluated for impairment	0	0
Loans collectively evaluated for impairment	0	0
Total	$ 0	$ 0

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Provision Benefit for Loan and Lease Net

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Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

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