Real Estate and Lending Activities - Assets Acquired (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013
Significant Acquisitions and Disposals [Line Items]
Total assets acquired	$ 182,982		$ 371,500
Total assets acquired	436,386	431,024
Net investments in direct financing leases [Member]
Significant Acquisitions and Disposals [Line Items]
Total assets acquired			85,000
Land [Member]
Significant Acquisitions and Disposals [Line Items]
Total assets acquired	13,058		16,220
Building [Member]
Significant Acquisitions and Disposals [Line Items]
Total assets acquired	152,096		265,030
Intangible lease assets - subject to amortization [Member]
Significant Acquisitions and Disposals [Line Items]
Total assets acquired	12,828
Other loans [Member]
Significant Acquisitions and Disposals [Line Items]
Total assets acquired	$ 5,000		$ 5,250