Related-Party Transactions - Rent Income - Schedule of Future Minimum Rental Income (Parenthetical) (Detail)	12 Months Ended
Dec. 31, 2012
Operating Leased Assets [Line Items]
Mortgages mature date	Jan. 05, 2015
Additional basic rent resulting period	After January 2015

Date the derivative contract matures, in CCYY-MM-DD format.

No definition available.

Name:	us-gaap_DerivativeMaturityDates
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration