List of Assets Purchased and Invested as Part of Acquisitions (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Jun. 30, 2011
Significant Acquisitions and Disposals [Line Items]
Total assets acquired	$ 396,500	$ 194,579
Total liabilities assumed		(14,592)
Net assets acquired	396,500	179,987
Land
Significant Acquisitions and Disposals [Line Items]
Total assets acquired		16,151
Building
Significant Acquisitions and Disposals [Line Items]
Total assets acquired		157,834
Intangible Lease Assets
Significant Acquisitions and Disposals [Line Items]
Total assets acquired		14,093
Net Investment in Direct Financing Leases
Significant Acquisitions and Disposals [Line Items]
Total assets acquired	200,000
Mortgage Loans on Real Estate
Significant Acquisitions and Disposals [Line Items]
Total assets acquired	100,000
Other loans
Significant Acquisitions and Disposals [Line Items]
Total assets acquired	93,200	5,233
Equity Investments
Significant Acquisitions and Disposals [Line Items]
Total assets acquired	$ 3,300	$ 1,268