DEPOSITS AND CUSTOMER REPURCHASE AGREEMENTS DEPOSITS AND CUSTOMER REPURCHASE AGREEMENTS (Certificates of Deposit by Balance) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Time Deposits [Abstract]
Certificates of deposit less than $250,000	$ 634,318banr_TimeDeposits100000to250000	$ 629,345banr_TimeDeposits100000to250000
Certificates of deposit $250,000 and greater	143,731banr_TimeDepositsMorethan250000	141,171banr_TimeDepositsMorethan250000
Total certificate accounts	$ 778,049	$ 770,516

Amount of interest-bearing domestic certificate of deposit liabilities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.12)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 12

-Article 9

Name:	us-gaap_InterestBearingDomesticDepositCertificatesOfDeposits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant