Real Estate and Lending Activities - Components of Net Investment in Direct Financing Leases (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Business Combinations [Abstract]
Minimum lease payments receivable	$ 1,566,155	$ 1,277,923
Estimated residual values	211,283	201,283
Less: Unearned income	(1,373,926)	(1,164,794)
Net investment in direct financing leases	$ 403,512	$ 314,412

The net amount due as of the balance sheet date consisting of: (a) minimum lease payments due on direct financing and sales-type leases, (b) unguaranteed residual value, and (c) any unamortized initial direct costs on direct financing leases; less: (i) executory costs, (ii) unearned income, and (iii) the accumulated allowance for uncollectible minimum lease payments.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 30

-Section 50

-Paragraph 4

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=25496975&loc=d3e45377-112738

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