Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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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 and after 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.

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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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LOANS AND LEASES AND ALLOWANCE FOR LOAN AND LEASE LOSSES - Schedule of Loans and Leases Receivable (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 7,253,293		$ 6,659,407	$ 6,226,897
Allowance for loan and lease losses	(57,782)	$ (56,678)	(49,333)	(45,072)	$ (42,385)	$ (40,444)
Loans and leases receivable, net	7,195,511		6,610,074
NTM Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	834,301		806,933
Traditional Loans and Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	6,418,992		5,852,474
Traditional Loans and Leases \| Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	200,294		182,960
Commercial \| Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,673,055		1,701,951	1,602,805
Allowance for loan and lease losses	(16,543)	(16,864)	(14,280)	(12,500)	(10,495)	(7,584)
Commercial \| Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	823,193		717,415	713,120
Allowance for loan and lease losses	(6,012)	(5,732)	(4,971)	(5,328)	(5,126)	(5,467)
Commercial \| Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	2,112,190		1,816,141	1,617,890
Allowance for loan and lease losses	(15,473)	(14,630)	(13,265)	(11,274)	(10,686)	(11,376)
Commercial \| SBA
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	71,494		78,699	78,604
Allowance for loan and lease losses	(1,870)	(1,840)	(1,701)	(1,297)	(1,084)	(939)
Commercial \| Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	200,294		182,960	176,397
Allowance for loan and lease losses	(3,247)	(3,419)	(3,318)	(3,212)	(2,974)	(2,015)
Commercial \| Lease financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		13	91
Allowance for loan and lease losses	0	$ 0	0	$ (2)	$ (3)	$ (6)
Commercial \| NTM Loans \| Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		0
Commercial \| NTM Loans \| Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		0
Commercial \| NTM Loans \| Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		0
Commercial \| NTM Loans \| SBA
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		0
Commercial \| NTM Loans \| Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		0
Commercial \| NTM Loans \| Lease financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		0
Commercial \| Traditional Loans and Leases \| Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,673,055		1,701,951
Commercial \| Traditional Loans and Leases \| Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	823,193		717,415
Commercial \| Traditional Loans and Leases \| Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	2,112,190		1,816,141
Commercial \| Traditional Loans and Leases \| SBA
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	71,494		78,699
Commercial \| Traditional Loans and Leases \| Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	200,294		182,960
Commercial \| Traditional Loans and Leases \| Lease financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		13
Consumer \| Single family residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	2,300,069		2,055,649
Consumer \| Other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	72,998		106,579
Consumer \| NTM Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	834,301		806,933
Consumer \| NTM Loans \| Single family residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	831,169		803,355
Consumer \| NTM Loans \| Other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	3,132		3,578
Consumer \| Traditional Loans and Leases \| Single family residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,468,900		1,252,294
Consumer \| Traditional Loans and Leases \| Other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 69,866		$ 103,001