Receivables Schedule of Notes Receivable by Segment (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Secured loans	$ 425,138	$ 223,029
Total Notes Receivable (net)	447,040	232,683
Finance [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Secured loans	425,138	223,029
Auction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Auction guarantee advances	16,224	7,512
Unsecured loan	2,142	2,142
Dealer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Secured loans	$ 3,536	$ 0

Represents the amount of guarantees advanced to a consignor prior to the sale date as of the balance sheet date.

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the aggregate value of notes receivable, collateralized by works of art, to pay the Company (holder) a definite sum of money, net of any write-downs taken for collection uncertainty on the part of the holder. Such amount may include accrued interest receivable in accordance with the terms of the debt. The debt also may contain provisions and related items including a discount or premium, payable on demand, secured, or unsecured, interest bearing or noninterest bearing, among myriad other features and characteristics.

+ References

No definition available.

+ Details

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Namespace Prefix:	bid_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

An amount representing an agreement for an unconditional promise by the maker, not collateralized by works of art, to pay the Company (holder) a definite sum of money, net of any write-downs taken for collection uncertainty on the part of the holder. Such amount may include accrued interest receivable in accordance with the terms of the debt. The debt also may contain provisions and related items including a discount or premium, payable on demand, secured, or unsecured, interest bearing or noninterest bearing, among myriad other features and characteristics.

+ References

No definition available.

+ Details

Name:	bid_UnsecuredLoans
Namespace Prefix:	bid_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

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

- Definition

Net amount of the investment in a contractual right to receive money on demand or on fixed or determinable dates that is recognized as an asset in the creditor's statement of financial position. Examples include, but are not limited to, credit card receivables, notes receivable and receivables relating to lessor's rights to payments from leases other than operating leases that have been recorded as assets. Excludes trade accounts receivable with contractual maturity of one year or less and arose from the sale of goods or services.

+ References

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 210.5-02.3)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 3

-Article 5

+ Details

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant