Indebtedness - Schedule of Debt (Parenthetical) (Detail) (North Point Center [Member], Interest Rate Swap Lock [Member], Note 5 [Member])	12 Months Ended
Dec. 31, 2014
North Point Center [Member] \| Interest Rate Swap Lock [Member] \| Note 5 [Member]
Debt Instrument [Line Items]
Stated interest rate, basis spread on variable rate	3.57%

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

No definition available.

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration