Commitments And Contingencies (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	0 Months Ended
Mar. 18, 2011	Dec. 31, 2014
Loss Contingency, Information about Litigation Matters [Abstract]
Loan Balance of Swap Commitment		$ 17,400oksb_LoanBalanceOfSwapCommitment
Loss Contingency, Lawsuit Filing Date	March 18, 2011

States the date the complaint was formally filed in a court of law, in arbitration or mediation.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14326-108349

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 4

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14435-108349

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 9

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14557-108349

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