Share-Based Compensation (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Share-based compensation, allocation and classification in financial statements [Abstract]
Compensation cost charged to income for the Company's share-based compensation plans	$ 2.0	$ 2.0	$ 3.9	$ 4.2
Share-based Payment Arrangement, Amount Capitalized	$ 0.1	$ 0.1	$ 0.2	$ 0.2
2018 Omnibus Plan [Member]
Deferred compensation arrangements [Abstract]
Aggregate number of Company common shares or Operating Partnership units approved for awards under the 2018 Omnibus Plan, amended (in shares)	2,800,000		2,800,000
The ratio at which awards granted are deducted from the shares available for grant			one share or TRG Profits Unit for every one share or TRG Profits Unit granted
Profits Units [Member]
Deferred compensation arrangements [Abstract]
Awards under the Omnibus Plan			represents a contingent right to receive a TRG Unit upon vesting and the satisfaction of certain tax-driven requirements and, as to the TSR and NOI Performance-based TRG Profits Units, the satisfaction of certain performance-based requirements. Until vested, a TRG Profits Unit entitles the holder to only one-tenth of the distributions otherwise payable by TRG on a TRG Unit. Therefore, we account for these TRG Profits Units as participating securities in TRG. A portion of the TRG Profits Units award represents estimated cash distributions that otherwise would have been payable during the vesting period and, upon vesting, there will be an adjustment in actual number of TRG Profits Units realized under each award to reflect TRG's actual cash distributions during the vesting period
Restricted TRG Profits Units [Member]
Summary of non-option activity [Roll Forward]
Outstanding at January 1, 2020			22,411
Outstanding at beginning of period, weighted average grant date fair value (in dollars per share)			$ 54.73
Units recovered and cancelled (1)			(58)
Units recovered and cancelled (1), weighted average grant date fair value (in dollars per share)			$ 57.84
Vested			(14,199)
Vested, weighted average grant date fair value (in dollars per share)			$ 57.84
Outstanding at June 30, 2020	8,154		8,154
Outstanding at end of period, weighted average grant date fair value (in dollars per share)	$ 49.29		$ 49.29
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$ 0.1		$ 0.1
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition			8 months 12 days
TSR Performance-based TRG Profits Units [Member]
Summary of non-option activity [Roll Forward]
Outstanding at January 1, 2020			50,420
Outstanding at beginning of period, weighted average grant date fair value (in dollars per share)			$ 22.81
Units recovered and cancelled (1)			(27,318)
Units recovered and cancelled (1), weighted average grant date fair value (in dollars per share)			$ 23.14
Vested			(4,757)
Vested, weighted average grant date fair value (in dollars per share)			$ 23.14
Outstanding at June 30, 2020	18,345		18,345
Outstanding at end of period, weighted average grant date fair value (in dollars per share)	$ 22.22		$ 22.22
Target Grant Amount			300.00%
Weighted Average Payout Rate for Vesting During Period			17.00%
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$ 0.1		$ 0.1
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition			8 months 12 days
NOI Performance-based TRG Profits Units [Member]
Summary of non-option activity [Roll Forward]
Outstanding at January 1, 2020			50,420
Outstanding at beginning of period, weighted average grant date fair value (in dollars per share)			$ 2.99
Units recovered and cancelled (1)			(32,075)
Units recovered and cancelled (1), weighted average grant date fair value (in dollars per share)			$ 0
Outstanding at June 30, 2020	18,345		18,345
Outstanding at end of period, weighted average grant date fair value (in dollars per share)	$ 8.21		$ 8.21
Target Grant Amount			300.00%
Weighted Average Payout Rate for Vesting During Period			0.00%
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$ 0.1		$ 0.1
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition			8 months 12 days
TSR Performance Shares [Member]
Deferred compensation arrangements [Abstract]
Awards under the Omnibus Plan			represents the right to receive, upon vesting, shares of common stock ranging from 0-300% of the TSR PSU based on our market performance relative to that of a peer group. The TSR PSU grants include a cash payment upon vesting equal to the aggregate cash dividends that would have been paid on such shares of common stock during the vesting period.
Summary of non-option activity [Roll Forward]
Outstanding at January 1, 2020			29,375
Outstanding at beginning of period, weighted average grant date fair value (in dollars per share)			$ 82.95
Vested			(2,492)
Vested, weighted average grant date fair value (in dollars per share)			$ 79.60
Outstanding at June 30, 2020	26,883		26,883
Outstanding at end of period, weighted average grant date fair value (in dollars per share)	$ 83.26		$ 83.26
Actual Shares Issued Upon Vesting During Period			1,297
Weighted Average Payout Rate for Vesting During Period			52.00%
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$ 0.9		$ 0.9
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition			1 year 4 months 24 days
NOI Performance Shares [Member]
Deferred compensation arrangements [Abstract]
Awards under the Omnibus Plan			represents the right to receive, upon vesting, shares of common stock ranging from 0-300% of the NOI PSU based on our NOI performance, as well as a cash payment upon vesting equal to the aggregate cash dividends that would have been paid on such shares of common stock during the vesting period. These awards also provide for a cap on the maximum number of units vested if absolute TSR is not positive over a three-year period.
Summary of non-option activity [Roll Forward]
Outstanding at January 1, 2020			29,375
Outstanding at beginning of period, weighted average grant date fair value (in dollars per share)			$ 40.95
Granted			31,318
Granted, weighted average grant date value (in dollars per share)			$ 43.24
Vested			(2,492)
Vested, weighted average grant date fair value (in dollars per share)			$ 0
Outstanding at June 30, 2020	58,201		58,201
Outstanding at end of period, weighted average grant date fair value (in dollars per share)	$ 43.94		$ 43.94
Actual Shares Issued Upon Vesting During Period			0
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$ 1.7		$ 1.7
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition			1 year 10 months 24 days
Restricted Stock Units (RSUs) [Member]
Deferred compensation arrangements [Abstract]
Awards under the Omnibus Plan			represents the right to receive upon vesting one share of common stock, as well as a cash payment upon vesting equal to the aggregate cash dividends that would have been paid on such shares of common stock during the vesting period
Summary of non-option activity [Roll Forward]
Outstanding at January 1, 2020			179,846
Outstanding at beginning of period, weighted average grant date fair value (in dollars per share)			$ 57.73
Granted			84,352
Granted, weighted average grant date value (in dollars per share)			$ 47.07
Forfeited			(1,681)
Forfeited, Weighted Average Grant Date Fair Value (in dollars per share)			$ 56.55
Vested			(41,974)
Vested, weighted average grant date fair value (in dollars per share)			$ 67.05
Outstanding at June 30, 2020	220,543		220,543
Outstanding at end of period, weighted average grant date fair value (in dollars per share)	$ 51.89		$ 51.89
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$ 6.0		$ 6.0
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition			1 year 10 months 24 days
Unissued Partnership Units Under Unit Option Deferral Election Member
Share-based Payment Arrangement, Additional Disclosure [Abstract]
Options exercised under unit option deferral election plan (in shares)			3,000,000.0
The number of mature units tendered for the exercise of previously issued stock options under the unit option deferral election plan (in shares)			2,100,000
The number of units deferred under the unit option deferral election upon the exercise of previously issued stock options (in shares)			900,000
Date at which deferred partnership units begin to be issued			December 2022
Number of Annual Installments during which Deferred Partnership Units will be issued			five