Represents the balance of inventory held by an equity method investment of the entity

No definition available.

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

- Definition

Rerpresents the duration of the initial partnership agreement with a partner in one of the Company's equity method investments.

+ References

No definition available.

+ Details

Name:	bid_PeriodOfAmaPartnershipAgreement
Namespace Prefix:	bid_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the total sale price of an equity method investment sold by the entity.

+ References

No definition available.

+ Details

Name:	bid_SalesPriceofDisposalofEquityMethodInvestment
Namespace Prefix:	bid_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 323

-SubTopic 10

-Section 50

-Paragraph 3

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571

+ Details

Name:	us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of gain (loss) on sale or disposal of an equity method investment.

+ References

No definition available.

+ Details

Name:	us-gaap_EquityMethodInvestmentRealizedGainLossOnDisposal
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

+ 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 210.5-02.12)

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

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 323

-SubTopic 10

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=35755396&loc=d3e33749-111570

+ Details

Name:	us-gaap_EquityMethodInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The cash outflow associated with the purchase of or advances to an equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 13

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3213-108585

+ Details

Name:	us-gaap_PaymentsToAcquireEquityMethodInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash inflow associated with the sale of equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 12

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3179-108585

+ Details

Name:	us-gaap_ProceedsFromSaleOfEquityMethodInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

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

- Details

Name:	bid_FundingComponentsAxis=bid_UnsecuredLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	bid_FundingComponentsAxis=us-gaap_UpFrontPaymentArrangementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=bid_AmaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=bid_RMAuctionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Equity Method Investments (Details) (USD $)	3 Months Ended	12 Months Ended			0 Months Ended
Equity Method Investments (Details) (USD $)	Jun. 30, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Feb. 18, 2015	May 23, 1990
Schedule of Equity Method Investments [Line Items]
Carrying value of the Matisse Inventory		$ 44,800,000	$ 46,600,000
Carrying value of the Sotheby's investment		10,210,000us-gaap_EquityMethodInvestments	11,040,000us-gaap_EquityMethodInvestments
Sales Price of Disposal of Equity Method Investment	4,300,000
Equity method investment gain on disposal	300,000
Proceeds from Sale of Equity Method Investments		300,000	1,225,000	0
Unsecured Debt [Member]
Schedule of Equity Method Investments [Line Items]
Sales Price of Disposal of Equity Method Investment	3,500,000
Up-front Payment Arrangement [Member]
Schedule of Equity Method Investments [Line Items]
Proceeds from Sale of Equity Method Investments	800,000
RM Auctions [Member] \| Subsequent Event [Member]
Schedule of Equity Method Investments [Line Items]
Payments to Acquire Equity Method Investments					30,700,000
Inventory exchange rate of interest in partnership					25.00%
AMA [Member]
Schedule of Equity Method Investments [Line Items]
Payments to Acquire Equity Method Investments						153,000,000
Inventory exchange rate of interest in partnership		50.00%
Period of AMA Partnership Agreement		10 years
Carrying value of the Sotheby's investment		$ 10,200,000	$ 11,000,000