Acquired Intangible Assets and Liabilities (Details) (USD $)	3 Months Ended	12 Months Ended							3 Months Ended	12 Months Ended		9 Months Ended
	Dec. 31, 2010	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Above-market leases	Dec. 31, 2011 Above-market leases	Dec. 31, 2012 Below-market leases	Dec. 31, 2011 Below-market leases	Dec. 31, 2010 Other identified intangible assets	Dec. 31, 2012 Other identified intangible assets	Dec. 31, 2011 Other identified intangible assets	Sep. 27, 2010 Predecessor	Sep. 27, 2010 Predecessor Other identified intangible assets
Acquired Intangible Assets and Liabilities
New intangible assets added		$ 2,900,000		$ 82,100,000
New intangible liabilities added		200,000		15,700,000
Weighted average life of intangible assets		4 years 4 months 24 days		3 years 2 months 12 days
Weighted average life of intangible liabilities		6 months		10 years 9 months 18 days
Acquired Intangible Assets and Liabilities
Increase to rental income	400,000	1,500,000	1,700,000									600,000
Amortization of all other identified intangible assets	(390,000)	(1,505,000)	(1,650,000)						11,100,000	18,100,000	32,200,000	(171,000)	700,000
Estimated amortization of acquired below-market leases, net of acquired above-market leases
2013		758,000
2014		488,000
2015		544,000
2016		561,000
2017		592,000
Thereafter		3,211,000
Total		6,154,000
Estimated amortization of all other identified intangible assets
2013		7,405,000
2014		3,153,000
2015		2,071,000
2016		1,664,000
2017		1,174,000
Thereafter		1,601,000
Total		19,453,000	36,643,000
Lease contracts value, gross		45,700,000	61,600,000		6,800,000	8,700,000	18,600,000	21,100,000
Accumulated amortization		$ 28,600,000	$ 29,500,000		$ 4,500,000	$ 4,300,000	$ 10,100,000	$ 9,300,000