Fair Value Measurements - Additional Information (Details) $ in Thousands		3 Months Ended		9 Months Ended
	Jan. 01, 2019 USD ($) community	Sep. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($)	Dec. 31, 2018 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities					$ 49,790	$ 14,855
Debt					3,572,221	$ 3,640,180
Property, plant and equipment and leasehold intangibles, net		$ 2,500		$ 50,200
ASU 2016-02
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Operating lease right-of-use asset, number of communities impaired | community	25
Operating lease right-of-use assets	$ 56,600
Cumulative effect change in accounting principle	$ 58,100
Assisted Living and Memory Care
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill impairment			$ 351,700
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities					$ 49,800