Subsequent Events (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended		0 Months Ended		12 Months Ended		0 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Jan. 09, 2013 ATM 2012 Equity Sales Offering [Member]	Jan. 09, 2013 Greensboro, NC Office Properties Acquisition (2012) [Member] sqft property	Dec. 31, 2012 Highwoods Realty Limited Partnership [Member]	Dec. 31, 2011 Highwoods Realty Limited Partnership [Member]	Jan. 09, 2013 Highwoods Realty Limited Partnership [Member] ATM 2012 Equity Sales Offering [Member]	Jan. 09, 2013 Highwoods Realty Limited Partnership [Member] Greensboro, NC Office Properties Acquisition (2012) [Member] property sqft
Subsequent Event [Line Items]
Number of Common Stock sold at the market (in shares)	7,245,837	378,200	198,177		7,245,837	378,200	198,177
Average price of Common Stock sold at the market	$ 33.12	$ 35.09	$ 33.97		$ 33.12	$ 35.09	$ 33.97
Net proceeds of Common Stock sold at the market	$ 236.4	$ 13.1	$ 6.6		$ 236.4	$ 13.1	$ 6.6
Number of office properties acquired				2				2
Net rentable square feet of acquisition (in sqft)				195,000				195,000
Acquisition purchase price				30.9				30.9
Acquisition-related costs	$ 1.5			$ 0.2	$ 1.5			$ 0.2