Commitments and Contingencies - Additional Information (Details)	12 Months Ended
	Dec. 31, 2018 lease
Commitments and Contingencies Disclosure [Abstract]
Number of communities operated under long-term leases	343
Number of operating leases	252
Number of capital and financing leases	91
Initial lease terms, minimum	10 years
Initial lease terms, maximum	20 years
Renewal options, minimum	5 years
Renewal options, maximum	20 years
Remaining base lease terms, minimum	1 year
Remaining base lease terms, maximum	14 years