Investments in Real Estate - Preliminary Allocation of Purchase Price to Fair Values of Real Estate Acquired (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013
Business Combinations [Abstract]
Buildings, improvements and equipment	$ 22.3
Land	0.8
Total real estate	$ 23.1

Amount of acquisition cost of a business combination allocated to land included in real estate.

No definition available.

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