Accumulated Other Comprehensive Income (Loss) (Summary of Changes in Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands		1 Months Ended	3 Months Ended		6 Months Ended
		Mar. 31, 2022	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022		Jun. 30, 2021
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at the beginning of the period			$ 3,553,398	$ 3,661,267	$ 3,710,670		$ 3,715,023
Other comprehensive income (loss) before reclassifications			5,819	(1,136)	17,561		2,247
(Gain) loss reclassified from accumulated other comprehensive loss to net income			2,646	3,041	5,981		6,014
Share of investee’s other comprehensive income	[1]		0	1,358	0		2,575
Reclassification of the Company's share of previously deferred derivative gains to net income	[2]		0	0	(6,723)		0
Net current-period other comprehensive income (loss)			8,465	3,263	16,819		10,836
Balance at the end of the period		$ 3,553,398	3,443,801	3,671,903	3,443,801		3,671,903
Equity in earnings (losses) from real estate and other affiliates			(6,092)	7,867	11,820		23,663
AOCI, reclassification of cash flow hedge	[3]				6,723
Share of investee's other comprehensive income, tax expense (benefit)		1,900		386	1,912	[3]	732
Disposal Group, Disposed of by Sale, Not Discontinued Operations | 110 North Wacker
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Equity in earnings (losses) from real estate and other affiliates		8,600
AOCI, reclassification of cash flow hedge		6,700
AOCI Attributable to Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at the beginning of the period			(6,103)	(31,017)	(14,457)		(38,590)
Share of investee’s other comprehensive income				1,358			2,575
Balance at the end of the period		$ (6,103)	$ 2,362	$ (27,754)	2,362		$ (27,754)
AOCI, reclassification of cash flow hedge	[3]				$ 6,723

[1] Amount is shown net of tax expense of $0.4 million for the three months ended June 30, 2021, and $0.7 million for the six months ended June 30, 2021.

[2] 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.

[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.