CONDENSED CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands		Total		Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive (Loss) Income		Treasury Stock	Total Stockholders' Equity		Noncontrolling Interests		Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period of Adoption, Adjustment Accumulated Deficit	Cumulative Effect, Period of Adoption, Adjustment Total Stockholders' Equity
Balance at the beginning of the period (in shares) at Dec. 31, 2018				43,511,473
Balance at the beginning of the period at Dec. 31, 2018		$ 3,238,126		$ 436	$ 3,322,433	$ (120,341)	$ (8,126)		$ (62,190)	$ 3,132,212		$ 105,914
Balance at the beginning of the period (in shares) at Dec. 31, 2018									(519,849)
Increase (Decrease) in Stockholders' Equity
Net income (loss)		75,296				75,056				75,056		240
Interest rate swaps		(25,259)	[1]				(25,259)			(25,259)
Terminated swap amortization		(2,055)					(2,055)			(2,055)
Capitalized swap interest, net of tax		(73)	[2]				(73)			(73)
Deconsolidation of Associations of Unit Owners		(2,538)										(2,538)
Contributions to real estate and other affiliates		84,889										84,889
Stock plan activity (in shares)				241,304
Stock plan activity		11,670		$ 2	11,668					11,670
Balance at the end of the period (in shares) at Sep. 30, 2019				43,752,777
Balance at the end of the period at Sep. 30, 2019		3,380,056		$ 438	3,334,101	(45,285)	(35,513)		$ (62,190)	3,191,551		188,505
Balance at the end of the period (in shares) at Sep. 30, 2019									(519,849)
Balance at the beginning of the period (in shares) at Jun. 30, 2019				43,661,694
Balance at the beginning of the period at Jun. 30, 2019		3,351,767		$ 437	3,329,062	(75,043)	(28,542)		$ (62,190)	3,163,724		188,043
Balance at the beginning of the period (in shares) at Jun. 30, 2019									(519,849)
Increase (Decrease) in Stockholders' Equity
Net income (loss)		30,043				29,758				29,758		285
Interest rate swaps		(6,207)	[1]				(6,207)			(6,207)
Terminated swap amortization		(764)					(764)			(764)
Capitalized swap interest, net of tax	[2]	0
Deconsolidation of Associations of Unit Owners		177										177
Stock plan activity (in shares)				91,083
Stock plan activity		5,040		$ 1	5,039					5,040
Balance at the end of the period (in shares) at Sep. 30, 2019				43,752,777
Balance at the end of the period at Sep. 30, 2019		3,380,056		$ 438	3,334,101	(45,285)	(35,513)		$ (62,190)	3,191,551		188,505
Balance at the end of the period (in shares) at Sep. 30, 2019									(519,849)
Balance at the beginning of the period (in shares) at Dec. 31, 2019				43,635,893
Balance at the beginning of the period at Dec. 31, 2019		3,332,988		$ 437	3,343,983	(46,385)	(29,372)		$ (120,530)	3,148,133		184,855	[3]	$ (18)	$ (18)	$ (18)
Balance at the beginning of the period (in shares) at Dec. 31, 2019									(1,050,260)
Increase (Decrease) in Stockholders' Equity
Net income (loss), excluding $24,270 attributable to redeemable noncontrolling interest		(19,453)				(19,508)				(19,508)		55	[3]
Net income (loss)		4,817
Interest rate swaps		(24,558)	[1]				(24,558)			(24,558)
Terminated swap amortization		(1,835)					(1,835)			(1,835)
Reclassification of redeemable noncontrolling interest to temporary equity		(6,091)										(6,091)	[3]
Derecognition of 110 North Wacker	[4]	(165,509)				1	12,934			12,935		(178,444)	[3]
Capitalized swap interest, net of tax	[2]	0
Common stock issued (in shares)				12,270,900
Common stock issued		593,616		$ 123	593,493					593,616
Stock plan activity (in shares)				68,090					2,875
Stock plan activity		4,522		$ 1	4,697				$ (176)	4,522
Balance at the end of the period (in shares) at Sep. 30, 2020				55,974,883
Balance at the end of the period at Sep. 30, 2020		3,713,662		$ 561	3,942,173	(65,910)	(42,831)		$ (120,706)	3,713,287		375	[3]
Balance at the end of the period (in shares) at Sep. 30, 2020									(1,053,135)
Balance at the beginning of the period (in shares) at Jun. 30, 2020				55,981,559
Balance at the beginning of the period at Jun. 30, 2020		3,739,703		$ 561	3,941,516	(205,621)	(61,111)		$ (120,530)	3,554,815		184,888	[3]
Balance at the beginning of the period (in shares) at Jun. 30, 2020									(1,050,260)
Increase (Decrease) in Stockholders' Equity
Net income (loss), excluding $24,270 attributable to redeemable noncontrolling interest		139,732				139,710				139,710		22	[3]
Net income (loss)		164,002
Interest rate swaps		5,923	[1]				5,923			5,923
Terminated swap amortization		(577)					(577)			(577)
Reclassification of redeemable noncontrolling interest to temporary equity		(6,091)										(6,091)	[3]
Derecognition of 110 North Wacker		(165,509)	[4]			1	12,934	[4]		12,935	[4]	(178,444)	[3],[4]
Capitalized swap interest, net of tax	[2]	0
Common stock issued		3			3					3
Stock plan activity (in shares)				(6,676)					2,875
Stock plan activity		478		$ 0	654				$ (176)	478
Balance at the end of the period (in shares) at Sep. 30, 2020				55,974,883
Balance at the end of the period at Sep. 30, 2020		$ 3,713,662		$ 561	$ 3,942,173	$ (65,910)	$ (42,831)		$ (120,706)	$ 3,713,287		$ 375	[3]
Balance at the end of the period (in shares) at Sep. 30, 2020									(1,053,135)

[1] Amounts are shown net of deferred tax expense of $1.3 million for the three months ended September 30, 2020, and a deferred tax benefit of $1.7 million for the three months ended September 30, 2019. Amounts are shown net of deferred tax benefit of $5.6 million for the nine months ended September 30, 2020, and $7.0 million for the nine months ended September 30, 2019.

[2] The deferred tax impact was zero for the three and nine months ended September 30, 2020, and the three months ended September 30, 2019, and not meaningful for the nine months ended September 30, 2019.

[3] Excludes redeemable noncontrolling interest, which is reflected in temporary equity. See Note 3 - Real Estate and Other Affiliates

[4] Related to deconsolidation of 110 North Wacker. Refer to Note 3 - Real Estate and Other Affiliates for additional information.