Loans Receivable, Net - Allowance for Loan Losses and Recorded Investment in Loans by Portfolio Segment and Based on Impairment Method Excluding PCI Loans (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Allowance for loan losses:
Balance at beginning of period	$ 16,577	$ 15,721
Provision (benefit) charged to operations	620	1,371
Charge-offs	(868)	(533)
Recoveries	376	258
Balance at end of period	16,705	16,817
Ending allowance balance attributed to loans:
Individually evaluated for impairment	604		$ 0
Collectively evaluated for impairment	16,101		16,577
Total ending allowance balance	16,705		16,577
Loans:
Loans individually evaluated for impairment	34,451		29,797
Loans collectively evaluated for impairment	5,927,418		5,550,015
Total loans	5,961,869		5,579,812
Commercial and Industrial
Allowance for loan losses:
Balance at beginning of period	1,609	1,801
Provision (benefit) charged to operations	(19)	470
Charge-offs	0	(44)
Recoveries	57	24
Balance at end of period	1,647	2,251
Ending allowance balance attributed to loans:
Individually evaluated for impairment	0		0
Collectively evaluated for impairment	1,647		1,609
Total ending allowance balance	1,647		1,609
Loans:
Loans individually evaluated for impairment	250		1,626
Loans collectively evaluated for impairment	380,097		303,368
Total loans	380,347		304,994
Commercial Real Estate – Owner Occupied
Allowance for loan losses:
Balance at beginning of period	2,277	3,175
Provision (benefit) charged to operations	1,550	(307)
Charge-offs	(389)	0
Recoveries	0	3
Balance at end of period	3,438	2,871
Ending allowance balance attributed to loans:
Individually evaluated for impairment	604		0
Collectively evaluated for impairment	2,834		2,277
Total ending allowance balance	3,438		2,277
Loans:
Loans individually evaluated for impairment	7,411		5,395
Loans collectively evaluated for impairment	793,879		734,980
Total loans	801,290		740,375
Commercial Real Estate – Investor
Allowance for loan losses:
Balance at beginning of period	8,770	7,952
Provision (benefit) charged to operations	(802)	879
Charge-offs	(21)	(123)
Recoveries	295	130
Balance at end of period	8,242	8,838
Ending allowance balance attributed to loans:
Individually evaluated for impairment	0		0
Collectively evaluated for impairment	8,242		8,770
Total ending allowance balance	8,242		8,770
Loans:
Loans individually evaluated for impairment	13,595		9,738
Loans collectively evaluated for impairment	2,136,296		2,005,472
Total loans	2,149,891		2,015,210
Residential Real Estate
Allowance for loan losses:
Balance at beginning of period	2,413	1,804
Provision (benefit) charged to operations	(23)	493
Charge-offs	(427)	(244)
Recoveries	2	85
Balance at end of period	1,965	2,138
Ending allowance balance attributed to loans:
Individually evaluated for impairment	0		0
Collectively evaluated for impairment	1,965		2,413
Total ending allowance balance	1,965		2,413
Loans:
Loans individually evaluated for impairment	10,028		10,064
Loans collectively evaluated for impairment	2,152,294		2,034,222
Total loans	2,162,322		2,044,286
Consumer
Allowance for loan losses:
Balance at beginning of period	486	614
Provision (benefit) charged to operations	(110)	(1)
Charge-offs	(31)	(122)
Recoveries	22	16
Balance at end of period	367	507
Ending allowance balance attributed to loans:
Individually evaluated for impairment	0		0
Collectively evaluated for impairment	367		486
Total ending allowance balance	367		486
Loans:
Loans individually evaluated for impairment	3,167		2,974
Loans collectively evaluated for impairment	464,852		471,973
Total loans	468,019		474,947
Unallocated
Allowance for loan losses:
Balance at beginning of period	1,022	375
Provision (benefit) charged to operations	24	(163)
Charge-offs	0	0
Recoveries	0	0
Balance at end of period	1,046	$ 212
Ending allowance balance attributed to loans:
Individually evaluated for impairment	0		0
Collectively evaluated for impairment	1,046		1,022
Total ending allowance balance	1,046		1,022
Loans:
Loans individually evaluated for impairment	0		0
Loans collectively evaluated for impairment	0		0
Total loans	$ 0		$ 0

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Provision Benefit for Loan and Lease Losses

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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 valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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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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