Fair Value Measurements (Details) (USD $)	3 Months Ended		6 Months Ended																																																																																										6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011	Dec. 31, 2011 Interest rate cap [Member] Mortgage [Member] CMBS loan [Member] PRP [Member]	Jun. 30, 2012 Interest rate cap [Member] Mortgage [Member] CMBS 2012 first mortgage loan [Member] New PRP [Member]	Mar. 27, 2012 Interest rate cap [Member] Mortgage [Member] CMBS 2012 first mortgage loan [Member] New PRP [Member]	Jun. 30, 2012 Fair Value, inputs, level 1 [Member] Secured debt [Member] Term loan facility [Member]		Jun. 30, 2012 Fair Value, inputs, level 1 [Member] Mortgage [Member] CMBS 2012 first mortgage loan [Member]		Jun. 30, 2012 Fair Value, inputs, level 1 [Member] Mezzanine mortgage debt [Member] CMBS 2012 first mezzanine loan [Member]		Jun. 30, 2012 Fair Value, inputs, level 1 [Member] Mezzanine mortgage debt [Member] CMBS 2012 second mezzanine loan [Member]		Jun. 30, 2012 Fair Value, inputs, level 1 [Member] Senior notes [Member]		Jun. 30, 2012 Fair Value, inputs, level 1 [Member] Unsecured debt [Member]		Jun. 30, 2012 Fair Value, inputs, level 1 [Member] Guaranteed debt [Member] RY-8, Inc. [Member] Variable interest entity, primary beneficiary [Member]		Jun. 30, 2012 Fair Value, inputs, level 2 [Member] Secured debt [Member] Term loan facility [Member]		Jun. 30, 2012 Fair Value, inputs, level 2 [Member] Mortgage [Member] CMBS 2012 first mortgage loan [Member]		Jun. 30, 2012 Fair Value, inputs, level 2 [Member] Mezzanine mortgage debt [Member] CMBS 2012 first mezzanine loan [Member]		Jun. 30, 2012 Fair Value, inputs, level 2 [Member] Mezzanine mortgage debt [Member] CMBS 2012 second mezzanine loan [Member]		Jun. 30, 2012 Fair Value, inputs, level 2 [Member] Senior notes [Member]		Jun. 30, 2012 Fair Value, inputs, level 2 [Member] Unsecured debt [Member]		Jun. 30, 2012 Fair Value, inputs, level 2 [Member] Guaranteed debt [Member] RY-8, Inc. [Member] Variable interest entity, primary beneficiary [Member]		Jun. 30, 2012 Fair Value, inputs, level 3 [Member] Secured debt [Member] Term loan facility [Member]		Jun. 30, 2012 Fair Value, inputs, level 3 [Member] Mortgage [Member] CMBS 2012 first mortgage loan [Member]		Jun. 30, 2012 Fair Value, inputs, level 3 [Member] Mezzanine mortgage debt [Member] CMBS 2012 first mezzanine loan [Member]		Jun. 30, 2012 Fair Value, inputs, level 3 [Member] Mezzanine mortgage debt [Member] CMBS 2012 second mezzanine loan [Member]		Jun. 30, 2012 Fair Value, inputs, level 3 [Member] Senior notes [Member]		Jun. 30, 2012 Fair Value, inputs, level 3 [Member] Unsecured debt [Member]		Jun. 30, 2012 Fair Value, inputs, level 3 [Member] Guaranteed debt [Member] RY-8, Inc. [Member] Variable interest entity, primary beneficiary [Member]		Dec. 31, 2011 Estimate of fair value [Member] Secured debt [Member] Term loan facility [Member]	Dec. 31, 2011 Estimate of fair value [Member] Secured debt [Member] Pre-funded revolving credit facility [Member]	Dec. 31, 2011 Estimate of fair value [Member] Senior notes [Member]	Jun. 30, 2012 Carrying value [Member] Secured debt [Member] Term loan facility [Member]		Dec. 31, 2011 Carrying value [Member] Secured debt [Member] Term loan facility [Member]	Dec. 31, 2011 Carrying value [Member] Secured debt [Member] Pre-funded revolving credit facility [Member]	Jun. 30, 2012 Carrying value [Member] Mortgage [Member] CMBS 2012 first mortgage loan [Member]		Jun. 30, 2012 Carrying value [Member] Mezzanine mortgage debt [Member] CMBS 2012 first mezzanine loan [Member]		Jun. 30, 2012 Carrying value [Member] Mezzanine mortgage debt [Member] CMBS 2012 second mezzanine loan [Member]		Jun. 30, 2012 Carrying value [Member] Senior notes [Member]		Dec. 31, 2011 Carrying value [Member] Senior notes [Member]	Jun. 30, 2012 Carrying value [Member] Unsecured debt [Member]		Jun. 30, 2012 Carrying value [Member] Guaranteed debt [Member] RY-8, Inc. [Member] Variable interest entity, primary beneficiary [Member]		Jun. 30, 2012 Fair value, measurements, recurring [Member] Fair Value, inputs, level 1 [Member]	Dec. 31, 2011 Fair value, measurements, recurring [Member] Fair Value, inputs, level 1 [Member]	Jun. 30, 2012 Fair value, measurements, recurring [Member] Fair Value, inputs, level 1 [Member] Money market funds [Member]	Dec. 31, 2011 Fair value, measurements, recurring [Member] Fair Value, inputs, level 1 [Member] Money market funds [Member]	Jun. 30, 2012 Fair value, measurements, recurring [Member] Fair Value, inputs, level 2 [Member]	Dec. 31, 2011 Fair value, measurements, recurring [Member] Fair Value, inputs, level 2 [Member]	Jun. 30, 2012 Fair value, measurements, recurring [Member] Fair Value, inputs, level 2 [Member] Money market funds [Member]	Dec. 31, 2011 Fair value, measurements, recurring [Member] Fair Value, inputs, level 2 [Member] Money market funds [Member]	Jun. 30, 2012 Fair value, measurements, recurring [Member] Fair Value, inputs, level 3 [Member]	Dec. 31, 2011 Fair value, measurements, recurring [Member] Fair Value, inputs, level 3 [Member]	Jun. 30, 2012 Fair value, measurements, recurring [Member] Fair Value, inputs, level 3 [Member] Money market funds [Member]	Dec. 31, 2011 Fair value, measurements, recurring [Member] Fair Value, inputs, level 3 [Member] Money market funds [Member]	Jun. 30, 2012 Fair value, measurements, recurring [Member] Carrying value [Member]	Dec. 31, 2011 Fair value, measurements, recurring [Member] Carrying value [Member]	Jun. 30, 2012 Fair value, measurements, recurring [Member] Carrying value [Member] Money market funds [Member]	Dec. 31, 2011 Fair value, measurements, recurring [Member] Carrying value [Member] Money market funds [Member]	Jun. 30, 2012 Fair value, measurements, nonrecurring [Member] Fair Value, inputs, level 1 [Member] Assets measured with impairment in the three months ended June 30, 2012 [Member]	Jun. 30, 2012 Fair value, measurements, nonrecurring [Member] Fair Value, inputs, level 1 [Member] Assets measured with impairment in the six months ended June 30, 2012 [Member]	Jun. 30, 2012 Fair value, measurements, nonrecurring [Member] Fair Value, inputs, level 2 [Member] Assets measured with impairment in the three months ended June 30, 2012 [Member]	Jun. 30, 2012 Fair value, measurements, nonrecurring [Member] Fair Value, inputs, level 2 [Member] Assets measured with impairment in the six months ended June 30, 2012 [Member]	Jun. 30, 2012 Fair value, measurements, nonrecurring [Member] Fair Value, inputs, level 3 [Member] Assets measured with impairment in the three months ended June 30, 2012 [Member]	Jun. 30, 2012 Fair value, measurements, nonrecurring [Member] Fair Value, inputs, level 3 [Member] Assets measured with impairment in the six months ended June 30, 2012 [Member]	Jun. 30, 2012 Fair value, measurements, nonrecurring [Member] Fair Value, inputs, level 3 [Member] Long-lived assets held-for-use [Member]	Jun. 30, 2012 Fair value, measurements, nonrecurring [Member] Fair Value, inputs, level 3 [Member] Long-lived assets held-for-use [Member] Weighted average [Member]	Jun. 30, 2012 Fair value, measurements, nonrecurring [Member] Fair Value, inputs, level 3 [Member] Long-lived assets held-for-use [Member] Minimum [Member]		Jun. 30, 2012 Fair value, measurements, nonrecurring [Member] Fair Value, inputs, level 3 [Member] Long-lived assets held-for-use [Member] Maximum [Member]		Jun. 30, 2012 Fair value, measurements, nonrecurring [Member] Carrying value [Member] Assets measured with impairment in the three months ended June 30, 2012 [Member]	Jun. 30, 2012 Fair value, measurements, nonrecurring [Member] Carrying value [Member] Assets measured with impairment in the six months ended June 30, 2012 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents																																																																									$ 208,000	$ 30,208,000			$ 0	$ 0			$ 0	$ 0			$ 208,000	$ 30,208,000
Restricted cash																																																																									23,084,000	7,499,000			0	0			0	0			23,084,000	7,499,000
Total recurring fair value measurements																																																																							23,292,000	37,707,000			0	0			0	0			23,292,000	37,707,000
Money market funds, net value per dollar invested ratio	1		1		1
Notional amount of interest rate derivatives						775,700,000		48,700,000
Interest rate derivatives fair market value						0	0
Long-lived assets held and used, fair value disclosure																																																																																							0	0	0	650,000	2,075,000	2,283,000							2,075,000	2,933,000
Long-lived assets held and used, losses	4,654,000	0	9,088,000	0
Fair Value Inputs [Abstract]
Weighted-average cost of capital																																																																																														10.90%	10.40%	[1]	11.20%	[1]
Long-term growth rate																																																																																													3.00%
Annual revenue growth rate																																																																																														2.60%	(8.70%)	[2]	4.30%	[2]
Goodwill and other indefinite-lived intangible assets impairment	0	0
Loans payable									0	[3]	0	[4]	0	[4]	0	[4]							990,213,000	[3]	0	[4]	0	[4]	0	[4]							0	[3]	323,530,000	[4]	87,465,000	[4]	87,520,000	[4]							953,536,000	31,020,000		1,007,850,000	[3]	1,014,400,000	33,000,000	323,530,000	[4]	87,465,000	[4]	87,520,000	[4]
Notes payable																	0	[3]	0	[3]											254,897,000	[3]	0	[3]											0	[3]	8,585,000	[3]					254,277,000											248,075,000	[3]	248,075,000	9,213,000	[3]
Guaranteed debt																					$ 0	[3]													$ 0	[3]													$ 22,790,000	[3]																			$ 24,500,000	[3]

[1] Weighted average of the costs of capital unobservable input range for the six months ended June 30, 2012 was 10.9%.

[2] Weighted average of the annual revenue growth rate unobservable input range for the six months ended June 30, 2012 was 2.6%.

[3] Represents obligations of OSI.

[4] Represents obligations of New PRP.