Stockholder's Equity (Details) (USD $)	0 Months Ended	12 Months Ended				0 Months Ended						1 Months Ended	3 Months Ended	12 Months Ended					12 Months Ended			0 Months Ended
	Dec. 10, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 19, 2013	Dec. 19, 2013 Partnership Merger [Member]	Dec. 19, 2013 Parent Merger [Member]	Mar. 25, 2013 Pursuant to the exercise of the underwriters [Member]	Mar. 25, 2013 Public offering [Member]	May 18, 2011 Series D Cumulative Redeemable Preferred Stock [Member]	Aug. 12, 2010 Series D Cumulative Redeemable Preferred Stock [Member]	Jun. 30, 2003 Series D Cumulative Redeemable Preferred Stock [Member]	Jun. 30, 2013 Series D Cumulative Redeemable Preferred Stock [Member]	Dec. 31, 2013 Series D Cumulative Redeemable Preferred Stock [Member]	Dec. 31, 2012 Series D Cumulative Redeemable Preferred Stock [Member]	Dec. 31, 2011 Series D Cumulative Redeemable Preferred Stock [Member]	Dec. 31, 2012 Common Stock [Member]	Jun. 05, 2012 Common Stock [Member]	Dec. 31, 2012 Series E Preferred Stock [Member]	Aug. 01, 2012 Series E Preferred Stock [Member]	Jun. 05, 2012 Series E Preferred Stock [Member]	Feb. 11, 2014 Subsequent Event [Member]	Feb. 11, 2014 Subsequent Event [Member] Common Stock [Member]	Jan. 10, 2014 Subsequent Event [Member] Common Stock [Member]	Dec. 19, 2013 Thomas Properties Group, Inc. [Member]
Class of Stock [Line Items]
Stock issued		31,049,976	18,951,700	0						1,000,000	1,970,000	2,400,000											1,325,000	10,500,000
Preferred stock yield rate		8.00%	8.00%							8.00%	8.50%	8.00%		8.00%
Proceeds from issuance of preferred stock										$ 26,000,000		$ 58,000,000
Stock sale price (in usd per share)										$ 25.00	$ 23.757
Preferred stock, shares outstanding		0	5,421,296												5,400,000
Preferred stock, liquidation value (in usd per share)															$ 25
Preferred dividends declared (in usd per share)		$ 0.63	$ 2.00	$ 2.00										$ 0.63	$ 2.00	$ 2.00
Number of shares agreed to be sold in agreement																		4,300,000			13,500,000
Fair value of investment in company shares																		48,400,000			151,600,000
Transaction costs on equity issuance			13,900,000
Shares issued in lieu of director fees																	11,733		6,666
Common dividends paid			5,000,000
Preferred dividends paid																			1,000,000
Common shares issued upon conversion of preferred shares																				1
Payments for preferred stock redemption		135,532,000	0	0									136,300,000
Preferred stock redemption premium		6,604,000											6,600,000
Shares issued in previously announced public offering	13,500,000
Underwriters option for additional shares	1,200,000
Public offering price (in usd per share)	$ 13.00
Proceeds from public offering	184,800,000
Shares issued in transaction								1,650,000	11,000,000
Stock sale price (in usd per share)									$ 17.25
Net proceeds on transaction									209,000,000
Common stock, par value (in usd per share)		$ 0.001	$ 0.001		$ 0.001																				$ 0.01
Limited voting stock, par value (in usd per share)		$ 0.001	$ 0		$ 0.001																				$ 0.01
Merger common stock exchange ratio					0.3822
Common stock issued in merger (in shares)							17,820,962
Limited voting stock issued in merger (in shares)							4,451,461
LP Units issued in Merger						4,451,461
Share price					$ 18.05																		$ 18.15	$ 18.15
Proceeds from common stock issuance																						$ 205,500,000