Debt (Aggregate Future Principal And Interest Payments) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012
Debt Instruments [Abstract]
2012	$ 26,551
2013	206,927
2014	22,202
2015	306,604
Total future principal and interest payments	$ 562,284

Long-term Debt, Future Repayment of Principal or Interest Total

No definition available.

Name:	bid_LongTermDebtFutureRepaymentOfPrincipalOrInterestTotal
Namespace Prefix:	bid_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Long-term Debt, Maturities, Repayments of Principal and Interest in Next Twelve Months

No definition available.

Name:	bid_LongTermDebtMaturitiesRepaymentsOfPrincipalAndInterestInNextTwelveMonths
Namespace Prefix:	bid_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Long-term Debt, Maturities, Repayments of Principal and Interest in Year Four

No definition available.

Name:	bid_LongTermDebtMaturitiesRepaymentsOfPrincipalAndInterestInYearFour
Namespace Prefix:	bid_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Long-term Debt, Maturities, Repayments of Principal and Interest in Year Three

No definition available.

Name:	bid_LongTermDebtMaturitiesRepaymentsOfPrincipalAndInterestInYearThree
Namespace Prefix:	bid_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Long-term Debt, Maturities, Repayments of Principal Interest in Year Two

No definition available.

Name:	bid_LongTermDebtMaturitiesRepaymentsOfPrincipalInterestInYearTwo
Namespace Prefix:	bid_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

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