Other Real Estate Investments - Additional Information (Detail) $ in Millions	1 Months Ended	3 Months Ended	9 Months Ended
Dec. 31, 2014 USD ($) a bed	Sep. 30, 2015 USD ($)	Sep. 30, 2015 USD ($)
Real Estate Properties [Line Items]
Preferred equity investment		$ 8.2	$ 8.2
Recognized interest income		$ 0.2	$ 0.7
Signature Senior Living [Member]
Real Estate Properties [Line Items]
Preferred equity investment	$ 7.5
Return from preferred equity investment	12.00%
Number of beds planned for construction \| bed	134
Area under construction \| a	5
Initial lease yield	8.00%
Project construction completion year			2016

This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 323

-SubTopic 10

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=35755396&loc=d3e33749-111570

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.12)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant