Lease Amendments and Terminations and RIDEA Joint Ventures - Leases Amended (Details) (USD $)	12 Months Ended	0 Months Ended
	Dec. 31, 2014 item	Aug. 29, 2014 property item	Dec. 31, 2013
Lease Amendments And Terminations And Joint Venture Formations [Line Items]
Number Of Properties Contributed To Joint Venture	48
Initial direct costs and lease inducements	$ 146,500,000		$ 104,601,000
Straight-line rent receivable for former scheduled rent increases	355,864,000		368,919,000
Lease related net intangible assets	481,013,000		489,842,000
Brookdale Senior Living
Lease Amendments And Terminations And Joint Venture Formations [Line Items]
Number of communities sold in purchase option	8
Proceeds from communities sold in purchase option	51,000,000
Number of communities pending for sale in purchase option	1
Proceeds from communities pending for sale in purchase option	9,000,000
Brookdale Senior Living | Scenario, Forecast [Member]
Lease Amendments And Terminations And Joint Venture Formations [Line Items]
Annualized base rent reductions, first year	6,500,000
Annualized base rent reductions, subsequent years	7,500,000
Brookdale Senior Living | NNN-leased Portfolio
Lease Amendments And Terminations And Joint Venture Formations [Line Items]
Number of facilities for which existing lease agreement is amended		153
Number of properties with purchase options that will be cancelled on amendment		30
Average initial lease term		15 years
Number of extension options		2
Term of lease extension options		10 years
Business Combination, Consideration Transferred [Abstract]
Consideration paid to terminate purchase options		129,000,000
Rent concessions		76,000,000
Net consideration paid		$ 53,000,000