Loans and Credit Quality - Performing and Nonaccrual (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accrual	$ 5,347,705	$ 5,082,128
Nonaccrual	15,874	11,619
Total loans held for investment	5,363,579	5,093,747
Fair value of loans held for investment	4,830	4,057
Recurring [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Fair value of loans held for investment	4,830	4,057
Level 3 [Member] \| Recurring [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Fair value of loans held for investment	4,830	4,057
Consumer loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accrual	1,924,872	1,919,657
Nonaccrual	8,849	9,441
Total loans held for investment	1,933,721	1,929,098
Consumer loans [Member] \| Single family [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accrual	1,340,672	1,349,682
Nonaccrual	7,882	8,493
Total loans held for investment	1,348,554	1,358,175
Consumer loans [Member] \| Home equity and other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accrual	584,200	569,975
Nonaccrual	967	948
Total loans held for investment	585,167	570,923
Commercial real estate loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accrual	2,553,117	2,404,415
Nonaccrual	4,757	72
Total loans held for investment	2,557,874	2,404,487
Commercial real estate loans [Member] \| Non-owner occupied commercial real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accrual	780,928	701,928
Nonaccrual	11	0
Total loans held for investment	780,939	701,928
Commercial real estate loans [Member] \| Multifamily [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accrual	939,656	908,015
Nonaccrual	0	0
Total loans held for investment	939,656	908,015
Commercial real estate loans [Member] \| Construction/land development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accrual	832,533	794,472
Nonaccrual	4,746	72
Total loans held for investment	837,279	794,544
Commercial and industrial loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accrual	869,716	758,056
Nonaccrual	2,268	2,106
Total loans held for investment	871,984	760,162
Commercial and industrial loans [Member] \| Owner occupied commercial real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accrual	450,086	428,784
Nonaccrual	364	374
Total loans held for investment	450,450	429,158
Commercial and industrial loans [Member] \| Commercial business [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accrual	419,630	329,272
Nonaccrual	1,904	1,732
Total loans held for investment	$ 421,534	$ 331,004

Financing receivable that is considered to be performing and are still accruing interest.

No definition available.

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- Definition

Recorded investment in financing receivables that are on nonaccrual status as of the balance sheet date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5111-111524

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- Definition

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.

+ References

No definition available.

+ Details

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- Definition

Amount, before allowance and fees, of loans and leases receivable. 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 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4428-111522

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- Definition

Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-URI http://asc.fasb.org/subtopic&trid=2196772

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