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Represents the closing price that must be attained for at least 20 trading days in the period of 30 consecutive trading days at the end of the previous quarter in order for the Company's convertible debt to be eligible for conversion prior to conversion date as a percentage of the conversion price of the Company's convertible debt.

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The total of cash outflows paid and mortgages assumed for the acquisition of land and building.

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The cash outflow associated with convertible note hedge transactions.

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The initial amount of the liability for the conversion option reclassified to stockholders' equity when the embedded conversion option no longer required separation from the host instrument, net of taxes.

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Management's estimate of the company's nonconvertible borrowing rate as of the date of convertible note issuance.

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Represents the estimated fair value of favorable consignment terms provided to the prior landlord of the property.

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Net fair value as of the balance sheet date of derivative asset representing the fair value of the convertible note hedge instrument.

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The maximum amount by which the existing borrowing capacity of the credit facility may increase.

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The amount of stockholders' equity reclassified to assets because conditions for the convertible note hedge related to the Convertible Notes to be classified as equity were no longer met.

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The amount of the liability for the conversion option reclassfied to stockholders' equity when the embedded option no longer required separation from the host instrument, net of taxes.

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Noncash loss on the purchase of debt, net of fees.

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Management's estimate of the total conversion premium for conversion requests received.

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Management's estimate of the total conversion obligation for conversion requests received.

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The principal amount of Convertible Notes early conversion requests to be paid before the maturity date of the Convertible Notes.

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Aggregate principal amount of debt repurchased.

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Property Acquisition Price

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The amount of stockholders' equity reclassified to liabilities because conditions for the embedded conversion option within Convertible Notes to be classified as equity were no longer met.

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Aggregate life-to-date cash outflows to repurchase debt.

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Spread Over Federal Fund Rate

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Spread Over LIBOR

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Represents the stated interest rate of convertible debt.

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Unamortized Discount To Convertible Notes

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The exercise price of each class of warrants or rights outstanding.

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The portion of the carrying value of long-term convertible debt as of the balance sheet date that is scheduled to be repaid within one year or in the normal operating cycle if longer. Convertible debt is a financial instrument which can be exchanged for a specified amount of another security, typically the entity's common stock, at the option of the issuer or the holder.

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Carrying amount of long-term convertible debt as of the balance sheet date, net of the amount due in the next twelve months or greater than the normal operating cycle, if longer. The debt is convertible into another form of financial instrument, typically the entity's common stock.

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The price per share of the conversion feature embedded in the debt instrument.

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The ratio applied to the debt for purposes of determining the number of shares of the equity security into which the debt will be converted.

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The stated principal amount of the debt instrument at time of issuance, which may vary from the carrying amount because of unamortized premium or discount.

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Estimated fair value of the debt instrument at the balance-sheet date.

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Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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Interest rate stated in the contractual debt agreement.

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The amount of debt discount that was originally recognized at the issuance of the instrument that has yet to be amortized.

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Aggregate cash, stock, and paid-in-kind dividends declared for all securities (common shares, preferred shares) during the period.

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The per share amount of a dividend declared, but not paid, as of the financial reporting date.

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-Name Statement of Financial Accounting Standard (FAS)
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Net fair value as of the balance sheet date of the embedded derivative or group of embedded derivatives classified as assets, net of those classified as liabilities.

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The amount of the liability for the conversion option reclassified to stockholders' equity when the embedded option no longer required separation from the host instrument.

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Contracts and securities that allow the holder to buy common stock from the entity. A call option that gives the holder the right, but not the obligation, to purchase shares of common stock from the entity in accordance with an agreement upon payment of a specified amount. A warrant is a security that gives the holder the right to purchase common stock in accordance with the terms of the instrument, usually upon payment of a specified amount. The dilutive effect of which is reflected in diluted EPS by application of the treasury stock method unless another method is required to be applied.

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Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

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Reflects when the credit facility terminates, which may be presented in a variety of ways (year, month and year, day, month and year, quarter).

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Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

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The cash inflow from the issuance of debt instrument which can be exchanged for a specified amount of another security, typically the entity's common stock, at the option of the issuer or the holder.

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The cash inflow from a borrowing with the highest claim on the assets of the entity in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle, if longer).

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The cash inflow from issuance of rights to purchase common shares at predetermined price (usually issued together with corporate debt).

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Debt (Narrative) (Details) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	0 Months Ended	3 Months Ended	6 Months Ended			12 Months Ended		1 Months Ended				6 Months Ended							0 Months Ended	3 Months Ended			31 Months Ended		0 Months Ended	3 Months Ended	6 Months Ended			6 Months Ended
	Aug. 03, 2011	Jun. 30, 2011	Jun. 11, 2008	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010	Feb. 28, 2009	Feb. 29, 2008 Signing Of Related Purchase And Sale Agreement On January 11, 2008 [Member]	Feb. 28, 2009 Purchase Consummated On February 6, 2009 [Member]	Feb. 06, 2009 Assumption Of Existing Mortgage [Member]	Jun. 30, 2011 Assumption Of Existing Mortgage [Member]	Jun. 30, 2011 Minimum [Member] Convertible Notes [Member]	Jun. 30, 2011 Minimum [Member] Credit Agreement [Member]	Jun. 30, 2011 Minimum [Member] Dollar Index Rate Loans [Member]	Jun. 30, 2011 Minimum [Member] LIBOR Rate Loans [Member]	Jun. 30, 2011 Maximum [Member] Convertible Notes [Member]	Jun. 30, 2011 Maximum [Member] Dollar Index Rate Loans [Member]	Jun. 30, 2011 Maximum [Member] LIBOR Rate Loans [Member]	Jun. 17, 2008 Senior Notes [Member]	Dec. 31, 2010 Senior Notes [Member]	Mar. 31, 2009 Senior Notes [Member]	Dec. 31, 2008 Senior Notes [Member]	Dec. 31, 2010 Senior Notes [Member]	Jun. 30, 2011 Senior Notes [Member]	Jun. 28, 2011 Convertible Notes [Member]	Jun. 30, 2011 Convertible Notes [Member]	Jun. 30, 2011 Convertible Notes [Member]	Jun. 30, 2008 Convertible Notes [Member]	Jun. 11, 2008 Convertible Notes [Member]	Jun. 30, 2011 Convertible Note Hedge And Warrant Transactions [Member]	Jun. 30, 2011 Dollar Index Rate Loans [Member]	Jun. 30, 2011 Revolving Credit Facility [Member]	Jun. 30, 2011 Letter Of Credit [Member]
Current borrowing capacity																																$ 200,000,000	$ 10,000,000
Increase in borrowing capacity																																50,000,000
Available borrowing capacity																																98,300,000
Spread over Federal Fund Rate																															0.50%
Spread over LIBOR																															1.00%
Applicable margin over interest rate														1.50%	2.50%		2.00%	3.00%
York mortgage property maturity date				July 1, 2035
York mortgage annual interest rate				5.60%
York mortgage property fair value							212,100,000				232,000,000
Amortization of debt discount to interest expenses				22,900,000
Fees paid in conjunction with assumption of mortgage property										2,400,000
York mortgage property carrying value		218,000,000		218,000,000	217,200,000	217,500,000
York mortgage property current liability		3,100,000		3,100,000	2,700,000	3,100,000
Dividend declared per share	$ 0.05												$ 0.10
Dividends	3,400,000												8,000,000
Credit agreement maturity date				September 1, 2014
Debt instrument stated interest percentage		3.125%		3.125%															7.75%							3.125%	3.125%
Components of purchase price of land and buildings								50,000,000	85,000,000	235,000,000
Property acquisition price									370,000,000
Estimated fair value of favorable consignment terms for the future sale of art at Sotheby's auctions		3,800,000		3,800,000
Aggregate principal value of debt																			150,000,000									200,000,000
Principal amount of debt repurchased																							70,000,000
Debt instrument maturity date																			June 15, 2015						June 15, 2013
Proceeds from issuance of senior notes																			145,900,000
Effective interest rate																			8.00%
Life-to-date non-cash gain																							2,500,000
Purchase price																							65,300,000
Stated interest rate of convertible debt																												3.125%
Non-cash gain on repurchase of debt, net of fees																					1,000,000	7,800,000
Loss recognition on repurchase																				6,300,000
Debt instrument fair value																								87,600,000		283,300,000	283,300,000
Carrying amount reported in Long-Term Debt		166,600,000		166,600,000
Convertible notes conversion ratio																											29.4122
Convertible notes conversion price, per share		34		34																						34	34
Conversion per principal value of convertible notes				1,000
Principal amount of conversion requests from holders of the Convertible Notes		18,100,000																								18,100,000				18,100,000
Principal amount of Convertible Notes to be redeemed in the third quarter of 2011, net of unamortized discount		16,611,000		16,611,000
Convertible Notes, if-converted value in excess of closing price of common stock																											$ 44.20
Closing price of common share as percentage of conversion price																											130.00%
Debt instrument convertible number of common share																											5.8
Net proceed from convertible notes																											161,800,000	194,300,000
Number of trading days												20				30											30
Number of trading days out of 30 consecutive trading days for determining closing price												20				30
Management estimates, conversion obligation																											24,000,000
Management estimates, conversion premium																										6,000,000	6,000,000
Incremental Common Shares Attributable to Call Options and Warrants			5.8
Common stock price per share to be acquired through warrant																													$ 44.905
Cost of Convertible Notes Hedges			40,600,000
Fair value of asset representing Convertible Note Hedge																														8,200,000
Estimated debt rate																											7.75%
Unamortized discount to convertible notes																											16,800,000
Embedded net of tax																													22,500,000
Liability for the conversion option reclassified to shareholder's equity		18,400,000		18,400,000		21,000,000																							21,000,000
Embedded conversion option classified as equity				34,100,000	38,200,000	38,200,000																						38,200,000
Embedded conversion option																										4,100,000	4,100,000
Reduction of shareholder's equity related to embedded option																											2,600,000
Net proceeds from sale of warrant				22,300,000
Warrant exercise price																													$ 44.905
Unamortized discount		1,521,000		1,521,000
Increase to shareholders' equity related to embedded option																														$ 5,300,000