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Loans - Investment of Originated Loans Held-for-Investment by Loan Type and Credit Quality Indicator (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	$ 2,727,852	$ 2,678,877
Pass
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	2,707,528	2,657,356
Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	3,309	3,349
Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	17,015	18,172
Real Estate | Multifamily | Less Than 35% LTV
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	197,675	170,832
Real Estate | Multifamily | Less Than 35% LTV | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	197,675	170,832
Real Estate | Multifamily | Less Than 35% LTV | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	0	0
Real Estate | Multifamily | Less Than 35% LTV | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	0	0
Real Estate | Multifamily | Equal to or Greater than 35% LTV
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	1,783,769	1,763,114
Real Estate | Multifamily | Equal to or Greater than 35% LTV | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	1,777,587	1,756,882
Real Estate | Multifamily | Equal to or Greater than 35% LTV | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	607	613
Real Estate | Multifamily | Equal to or Greater than 35% LTV | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	5,575	5,619
Real Estate | Commercial mortgage | Less Than 35% LTV
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	79,492	79,312
Real Estate | Commercial mortgage | Less Than 35% LTV | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	79,101	78,917
Real Estate | Commercial mortgage | Less Than 35% LTV | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	391	395
Real Estate | Commercial mortgage | Less Than 35% LTV | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	0	0
Real Estate | Commercial mortgage | Equal to or Greater than 35% LTV
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	423,357	420,548
Real Estate | Commercial mortgage | Equal to or Greater than 35% LTV | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	412,573	409,155
Real Estate | Commercial mortgage | Equal to or Greater than 35% LTV | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	1,125	1,137
Real Estate | Commercial mortgage | Equal to or Greater than 35% LTV | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	9,659	10,256
Real Estate | One-to-four family residential mortgage | Less Than 60% LTV
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	57,784	57,065
Real Estate | One-to-four family residential mortgage | Less Than 60% LTV | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	55,956	54,912
Real Estate | One-to-four family residential mortgage | Less Than 60% LTV | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	740	747
Real Estate | One-to-four family residential mortgage | Less Than 60% LTV | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	1,088	1,406
Real Estate | One-to-four family residential mortgage | Equal to or Greater than 60% LTV
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	34,089	35,368
Real Estate | One-to-four family residential mortgage | Equal to or Greater than 60% LTV | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	33,751	34,808
Real Estate | One-to-four family residential mortgage | Equal to or Greater than 60% LTV | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	0	0
Real Estate | One-to-four family residential mortgage | Equal to or Greater than 60% LTV | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	338	560
Real Estate | Construction and land
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	30,199	26,613
Real Estate | Construction and land | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	30,199	26,613
Real Estate | Construction and land | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	0	0
Real Estate | Construction and land | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	0	0
Real Estate | Home equity and lines of credit
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	81,136	80,315
Real Estate | Home equity and lines of credit | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	80,902	80,077
Real Estate | Home equity and lines of credit | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	26	27
Real Estate | Home equity and lines of credit | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	208	211
Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	39,016	44,190
Commercial and Industrial | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	38,449	43,640
Commercial and Industrial | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	420	430
Commercial and Industrial | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	147	120
Other
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	1,335	1,520
Other | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	1,335	1,520
Other | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	0	0
Other | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	$ 0	$ 0

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+ References

No definition available.

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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. Includes loans held for sale. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7(a))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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