Organization (Narrative) (Detail)	6 Months Ended
	Jun. 30, 2012 Year acre Vehicle sqft	Jun. 30, 2011
Real Estate Properties [Line Items]
General and limited partnership interest in the operating partnership	88.50%	87.50%
Restriction on redemption of OP units from date of issuance (years)	1
One OP unit is equivalent to one share of Common Stock	1
Number of series of preferred units outstanding	1
OP unit conversion rate	1
Square footage of real estate property	44,703
Area of parking in square feet	15,200,000
Area of undeveloped land parcels owned in acres	510.5
Value-added fund institutional investors	2
Commercial Real Estate Properties [Member]
Real Estate Properties [Line Items]
Number of real estate properties	150
Number of real estate properties	42,800,000
Total Properties Under Construction [ Member]
Real Estate Properties [Line Items]
Number of real estate properties	6
Number of real estate properties	2,200,000
Hotel Property [ Member]
Real Estate Properties [Line Items]
Number of real estate properties	1
Retail Properties [ Member]
Real Estate Properties [Line Items]
Number of real estate properties	3
Residential Properties [Member]
Real Estate Properties [Line Items]
Number of real estate properties	3
Residential Properties Under Construction [Member]
Real Estate Properties [Line Items]
Number of real estate properties	1
Investments Through Value-Added Fund [Member]
Real Estate Properties [Line Items]
Number of real estate properties	24
Total Office Properties [ Member]
Real Estate Properties [Line Items]
Number of real estate properties	143
Class A Office Properties [ Member]
Real Estate Properties [Line Items]
Number of real estate properties	126
Office Properties Under Construction [ Member]
Real Estate Properties [Line Items]
Number of real estate properties	5
Office/Technical Properties [ Member]
Real Estate Properties [Line Items]
Number of real estate properties	17