Fair Value Measurements - Additional Information (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($) community lease	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) community lease	Jun. 30, 2019 USD ($)	Mar. 31, 2020 USD ($) community	Dec. 31, 2019 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	$ 109,873		$ 109,873			$ 68,567
Line of credit, borrowings outstanding	166,381		166,381			0
Debt	$ 3,692,365		$ 3,692,365			3,555,123
Number of communities leased | lease	237		237
Operating lease, right of use assets impairment charge	$ 6,600		$ 72,300
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	109,900		109,900
Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Operating lease, right of use assets impairment charge	6,600	$ 0	72,300	$ 0
Property, plant and equipment and leasehold intangibles impairment charge	$ 3,700	$ 1,200	$ 14,700	$ 1,200
Condensed Consolidated Balance Sheet
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of communities leased | community	9		9		35
Estimated fair value	$ 10,300		$ 10,300		$ 106,700
Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	11.20%		11.20%
Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	12.30%		12.30%
Long-term debt and lines of credit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt	$ 3,900,000		$ 3,900,000			$ 3,600,000
Fifth Amended and Restated Credit Agreement | Line of Credit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Line of credit, borrowings outstanding	$ 166,400		$ 166,400		$ 166,400