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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Loans - Net Loans Held-for-Investment (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
Loans and Leases Receivable Disclosure [Line Items]
Loans held-for-investment, net	$ 3,338,778		$ 3,245,170
Allowance for loan losses	(27,832)	$ (27,486)	(27,497)	$ (26,882)	$ (26,172)	$ (26,160)
Net loans held-for-investment	3,310,946		3,217,673
Originated
Loans and Leases Receivable Disclosure [Line Items]
Loans	44,688		45,623
Deferred loan cost, net	7,436		6,892
Loans held-for-investment, net	2,800,816		2,678,877
Allowance for loan losses	(26,687)	(26,476)	(26,487)	(25,931)	(25,218)	(25,172)
Purchased Credit-Impaired
Loans and Leases Receivable Disclosure [Line Items]
Loans held-for-investment, net	18,077		20,143
Allowance for loan losses	(1,010)	(1,010)	(1,010)	(951)	(951)	(951)
Acquired Loans
Loans and Leases Receivable Disclosure [Line Items]
Loans	519,885		546,150
Loans held-for-investment, net	519,885		546,150
Allowance for loan losses	(135)	0	0	0	(3)	(37)
Real Estate \| Originated
Loans and Leases Receivable Disclosure [Line Items]
Loans	2,748,692		2,626,362
Real Estate \| Originated \| Multifamily
Loans and Leases Receivable Disclosure [Line Items]
Loans	2,029,205		1,930,535
Loans held-for-investment, net	2,032,518		1,933,946
Allowance for loan losses	(18,384)	(18,346)	(18,084)	(17,603)	(17,412)	(17,374)
Real Estate \| Originated \| Commercial
Loans and Leases Receivable Disclosure [Line Items]
Loans	511,711		499,311
Loans held-for-investment, net	512,308		499,860
Allowance for loan losses	(5,331)	(5,382)	(5,630)	(5,718)	(5,213)	(5,196)
Real Estate \| Originated \| One-to-Four Family
Loans and Leases Receivable Disclosure [Line Items]
Loans	88,713		91,371
Loans held-for-investment, net	90,232		92,433
Allowance for loan losses	(234)	(370)	(342)	(384)	(455)	(503)
Real Estate \| Originated \| Home equity and lines of credit
Loans and Leases Receivable Disclosure [Line Items]
Loans	85,506		78,593
Loans held-for-investment, net	87,389		80,315
Allowance for loan losses	(417)	(336)	(291)	(279)	(225)	(122)
Real Estate \| Originated \| Construction and Land
Loans and Leases Receivable Disclosure [Line Items]
Loans	33,557		26,552
Loans held-for-investment, net	33,573		26,613
Allowance for loan losses	(584)	(574)	(463)	(438)	(463)	(610)
Real Estate \| Acquired Loans
Loans and Leases Receivable Disclosure [Line Items]
Loans	509,939		534,211
Real Estate \| Acquired Loans \| Multifamily
Loans and Leases Receivable Disclosure [Line Items]
Loans	131,628		145,485
Real Estate \| Acquired Loans \| Commercial
Loans and Leases Receivable Disclosure [Line Items]
Loans	125,599		133,263
Real Estate \| Acquired Loans \| One-to-Four Family
Loans and Leases Receivable Disclosure [Line Items]
Loans	229,941		225,877
Real Estate \| Acquired Loans \| Home equity and lines of credit
Loans and Leases Receivable Disclosure [Line Items]
Loans	14,390		17,583
Real Estate \| Acquired Loans \| Construction and Land
Loans and Leases Receivable Disclosure [Line Items]
Loans	8,381		12,003
Commercial and Industrial \| Originated
Loans and Leases Receivable Disclosure [Line Items]
Loans	42,660		44,104
Loans held-for-investment, net	42,768		44,190
Allowance for loan losses	(1,591)	(1,376)	(1,569)	(1,402)	(1,337)	(1,273)
Commercial and Industrial \| Acquired Loans
Loans and Leases Receivable Disclosure [Line Items]
Loans	9,942		11,933
Other \| Originated
Loans and Leases Receivable Disclosure [Line Items]
Loans	2,028		1,519
Loans held-for-investment, net	2,028		1,520
Allowance for loan losses	(146)	$ (92)	(108)	$ (107)	$ (113)	$ (94)
Other \| Acquired Loans
Loans and Leases Receivable Disclosure [Line Items]
Loans	$ 4		$ 6