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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.

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Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

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Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Goodwill and Other Intangible Assets (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	May 01, 2014	Jul. 15, 2013	Jan. 09, 2013
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 119,029,000us-gaap_Goodwill	$ 29,365,000us-gaap_Goodwill
Goodwill impairment charges	0us-gaap_GoodwillImpairmentLoss	0us-gaap_GoodwillImpairmentLoss	0us-gaap_GoodwillImpairmentLoss
Washington Banking
Finite-Lived Intangible Assets [Line Items]
Goodwill additions	89,700,000
Goodwill				89,664,000
Washington Banking \| Core Deposits
Finite-Lived Intangible Assets [Line Items]
Useful life	10 years
Valley Bank
Finite-Lived Intangible Assets [Line Items]
Goodwill additions		16,400,000
Goodwill					16,353,000
Valley Bank \| Core Deposits
Finite-Lived Intangible Assets [Line Items]
Useful life	10 years
Northwest Commercial Bank
Finite-Lived Intangible Assets [Line Items]
Goodwill						$ (399,000)
Northwest Commercial Bank \| Core Deposits
Finite-Lived Intangible Assets [Line Items]
Useful life	5 years
Pierce Commercial Bank \| Core Deposits
Finite-Lived Intangible Assets [Line Items]
Useful life	4 years
Cowlitz Bank \| Core Deposits
Finite-Lived Intangible Assets [Line Items]
Useful life	9 years
Western Washington Bancorp \| Core Deposits
Finite-Lived Intangible Assets [Line Items]
Useful life	8 years