Accumulated Other Comprehensive Income (Loss) (Summary of Changes in Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands		1 Months Ended	3 Months Ended
		Mar. 31, 2022	Mar. 31, 2022		Mar. 31, 2021
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at the beginning of the period			$ 3,710,670		$ 3,715,023
Other comprehensive income (loss) before reclassifications			11,742		3,383
(Gain) loss reclassified from accumulated other comprehensive loss to net income			3,335		2,973
Reclassification of the Company's share of previously deferred derivative gains to net income	[1]		(6,723)
Share of investee’s other comprehensive income	[2]				1,217
Net current-period other comprehensive income			8,354		7,573
Balance at the end of the period		$ 3,553,398	3,553,398		3,661,267
AOCI, reclassification of cash flow hedge	[3]		6,723
Equity in earnings (losses) from real estate and other affiliates			17,912		15,796
Share of investee's other comprehensive income, tax expense (benefit)		1,900	1,912	[3]	346
Disposal Group, Disposed of by Sale, Not Discontinued Operations | 110 North Wacker
AOCI Attributable to Parent, Net of Tax [Roll Forward]
AOCI, reclassification of cash flow hedge		6,700
Equity in earnings (losses) from real estate and other affiliates		8,600
AOCI Attributable to Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at the beginning of the period			(14,457)		(38,590)
Share of investee’s other comprehensive income					1,217
Balance at the end of the period		$ (6,103)	(6,103)		$ (31,017)
AOCI, reclassification of cash flow hedge	[3]		$ 6,723

[1] In March 2022, the Company completed the sale of its ownership interest in 110 North Wacker and released a net of $6.7 million from Accumulated other comprehensive income (loss), representing the Company’s $8.6 million share of previously deferred gains associated with the Venture’s derivative instruments net of tax expense of $1.9 million. See Note 2 - Investment in Real Estate and Other Affiliates for additional information.

[2] Amount is shown net of tax expense of $0.3 million for the three months ended March 31, 2021.

[3] In March 2022, the Company completed the sale of its ownership interest in 110 North Wacker and released a net of $6.7 million from Accumulated other comprehensive income (loss), representing the Company’s $8.6 million share of previously deferred gains associated with the Venture’s derivative instruments net of tax expense of $1.9 million. See Note 2 - Investment in Real Estate and Other Affiliates for additional information.