Real Estate and Lending Activities - Assets Acquired (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Sep. 30, 2014
Business Acquisition [Line Items]
Total assets acquired	$ 2,022,926	$ 182,982
Land and Land Improvements [Member]
Business Acquisition [Line Items]
Total assets acquired	154,698	13,058
Building [Member]
Business Acquisition [Line Items]
Total assets acquired	748,854	152,096
Intangible lease assets - subject to amortization [Member]
Business Acquisition [Line Items]
Total assets acquired	66,461	12,828
Net investments in direct financing leases [Member]
Business Acquisition [Line Items]
Total assets acquired	170,700
Other loans [Member]
Business Acquisition [Line Items]
Total assets acquired	514,484	$ 5,000
Mortgage loans [Member]
Business Acquisition [Line Items]
Total assets acquired	$ 365,000