Summary of Significant Accounting Policies - Schedule of Company's Intangibles (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Assets:
Above-market leases, net	$ 38.6	$ 41.5
Liabilities:
Below-market leases, net	$ (139.3)us-gaap_BelowMarketLeaseNet	$ (123.9)us-gaap_BelowMarketLeaseNet

Amount after amortization of leases acquired as part of a real property acquisition at below market lease rate with a finite life.

No definition available.

Name:	us-gaap_BelowMarketLeaseNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant