Commitments And Contingencies (Details) In Millions	Jun. 30, 2011 USD ($)	Jun. 30, 2011 EUR (€)	Nov. 30, 2010 EUR (€)	Jun. 30, 2011 Non-Executive Officer [Member] USD ($)
Commitment for salaries and other cash compensation under employment arrangement	$ 23.7
Employment arrangement expiration date range start	February 2012	February 2012
Employment arrangement expiration date range end	March 2017	March 2017
Unfunded lending commitment to extend additional credit	11.6			0.7
UK collection pledged as collateral for loan		5
UK collection pledged as collateral as part of prior deed of loan pledged with bank			€ 20

Represents the aggregate remaining commitment for salaries and other cash compensation related to employment arrangements with certain senior employees as of the date of the balance sheet, exclusive of incentive and equity compensation.

Name:	bid_CommitmentForSalariesAndOtherCashCompensationUnderEmploymentArrangement
Namespace Prefix:	bid
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the last expiration date of the Company's material employment arrangements.

+ Details

Name:	bid_EmploymentArrangementExpirationDateRangeEnd
Namespace Prefix:	bid
Data Type:	us-types:dateStringItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the first expiration date of the Company's material employment arrangements.

+ Details

Name:	bid_EmploymentArrangementExpirationDateRangeStart
Namespace Prefix:	bid
Data Type:	us-types:dateStringItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the value of collateral underlying a loan made to a certain individual borrower.

+ Details

Name:	bid_ReceivablePledgedAsCollateralAsPartOfPriorDeedOfLoanPledgedWithBank
Namespace Prefix:	bid
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the amount of a loan made to a certain individual borrower.

+ Details

Name:	bid_UkCollectionPledgedAsCollateralForLoan
Namespace Prefix:	bid
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the value legally binding yet unfunded arrangements to lend, primarily on a collateralized basis and subject to certain limitations and conditions, to potential consignors and other individuals who have collections of art.

+ Details

Name:	bid_UnfundedLendingCommitmentToExtendAdditionalCredit
Namespace Prefix:	bid
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant