Summary of Significant Accounting Policies (Details) (USD $)	3 Months Ended		9 Months Ended					9 Months Ended		12 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 segment	Sep. 30, 2013	Sep. 30, 2014 American Multi-Cinema, Inc. [Member]	Sep. 30, 2013 American Multi-Cinema, Inc. [Member]	Sep. 30, 2014 ONTARIO Entertainment Retail Center Properties [Member] properties	Sep. 30, 2014 ONTARIO Four Entertainment Retail Centers [Member]	Sep. 30, 2013 ONTARIO Four Entertainment Retail Centers [Member]	Dec. 31, 2013 ONTARIO Four Entertainment Retail Centers [Member]	Sep. 30, 2014 Minimum [Member]	Sep. 30, 2014 Maximum [Member]	Sep. 30, 2014 Building [Member]	Sep. 30, 2014 Furniture, fixtures & equipment [Member] Minimum [Member]	Sep. 30, 2014 Furniture, fixtures & equipment [Member] Maximum [Member]	Sep. 30, 2014 Share Options [Member]	Sep. 30, 2013 Share Options [Member]	Sep. 30, 2014 Restricted Stock [Member] Employee [Member]	Sep. 30, 2013 Restricted Stock [Member] Employee [Member]	Sep. 30, 2014 Restricted Stock [Member] Minimum [Member] Employee [Member]	Sep. 30, 2014 Restricted Stock [Member] Maximum [Member] Employee [Member]	Sep. 30, 2014 Restricted Share Units [Member]	Sep. 30, 2014 Restricted Share Units [Member] Non-Employee Trustees [Member]	Sep. 30, 2013 Restricted Share Units [Member] Non-Employee Trustees [Member]
Operating Segments
Number of Reportable Operating Segments			4
Rental Properties [Abstract]
Estimated useful live of buildings (in years)													40 years	3 years	25 years
Revenue Recognition [Abstract]
Percentage rents			$ 1,700,000	$ 2,200,000
Mortgage And Other Participating Interest Income			1,400,000	900,000
Gain (Loss) on Contract Termination			123,000	0
Concentrations of Risk [Abstract]
Percent of megaplex theatre rental leased by AMC					26.00%
Rental revenue	74,410,000	62,209,000	210,759,000	182,758,000	65,500,000	63,600,000
Percentage of lease revenue in total revenue					23.00%	25.00%		11.00%	13.00%
Total revenue	98,738,000	87,841,000	280,381,000	253,714,000				30,200,000	31,700,000
Number of real estate properties (in properties)							4
Net assets of wholly owned subsidiaries								217,900,000		227,200,000
Wholly owned subsidiaries percentage in net assets								11.00%		13.00%
Share-based Compensation [Abstract]
Share based compensation			6,984,000	4,825,000
Share based compensation, future vesting period minimum (in years)			4 years								3 years	4 years				4 years				3 years	4 years
Range of settlement date for shares for non-employee trustee from grant date, minimum (in years)			1 year																			1 year
Stock-option expense																1,100,000	647,000
Share based compensation expense related to employees and trustees			$ 3,000,000															$ 5,100,000	$ 3,600,000				$ 797,000	$ 559,000