Business Acquisition, Equity Interests Issued or Issuable per Share Acquired.

No definition available.

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Namespace Prefix:	hmst_
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Balance Type:	na
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- Definition

Number of Branches Opened

+ References

No definition available.

+ Details

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- Definition

Number of shares of equity interests issued or issuable to acquire entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)(4)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

+ Details

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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

Price of a single share of a number of saleable stocks paid or offered to be paid in a business combination.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=109124213&loc=d3e6613-128477

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=109124213&loc=d3e6578-128477

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=77989000&loc=SL49117168-202975

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=99380562&loc=d3e13770-109266

+ Details

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Balance Type:	debit
Period Type:	instant

- Details

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- Details

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- Details

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- Details

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Business Combinations - Narrative (Details) $ / shares in Units, $ in Thousands	Sep. 15, 2017 USD ($) branch	Nov. 10, 2016 USD ($) branch	Aug. 12, 2016 USD ($) branch	Feb. 01, 2016 USD ($) $ / shares shares	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Business Acquisition [Line Items]
Goodwill from acquisition					$ 22,564	$ 22,564	$ 22,175
Opus Bank [Member]
Business Acquisition [Line Items]
Number of branches opened \| branch	1
Goodwill from acquisition	$ 389
Boston Private Bank and Trust [Member]
Business Acquisition [Line Items]
Number of branches opened \| branch		2
Goodwill from acquisition		$ 2,300
Bank of Oswego [Member]
Business Acquisition [Line Items]
Number of branches opened \| branch			2
Goodwill from acquisition			$ 19
OCBB [Member]
Business Acquisition [Line Items]
Goodwill from acquisition				$ 8,400
Purchase price of acquisition				$ 55,900
Number of equity interest issued and issuable per shares acquired				0.5206
Acquisition share price (in dollars per share) \| $ / shares				$ 1.1641
Number of shares of equity interest acquired \| shares				2,459,461