Accounts Payable, Accrued Liabilities, and Other Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Payables and Accruals [Abstract]
Refundable entrance fees	$ 301,953	$ 317,444
Construction related accrued liabilities	113,221	95,293
Accrued interest	55,373	78,735
Other accounts payable and accrued liabilities	217,911	271,919
Accounts payable, accrued liabilities, and other liabilities	688,458	763,391
Unamortized nonrefundable entrance fee	$ 485,000	$ 484,000