Subordinated debentures (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2018	Nov. 01, 2017
Subordinated Borrowing [Line Items]
Subordinated Borrowing, Interest Rate	5.875%
Debt Instrument, Interest Rate Terms	471.5
Pacific Continental [Member]
Subordinated Borrowing [Line Items]
Business Combination, Purchase Price Allocation, Subordinated Debt		$ 35.0

Description of the interest rate as being fixed or variable, and, if variable, identification of the index or rate on which the interest rate is based and the number of points or percentage added to that index or rate to set the rate, and other pertinent information, such as frequency of rate resets.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration