Summary of Significant Accounting Policies - Allowance for Credit Losses and Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Management Fees and Other Revenues
Insurance reserve for insurance subsidiaries and other self-insurance programs	$ 83,500	$ 88,100
Allowance for Credit Losses
Balance, beginning of period	30,094	33,282	$ 32,681
Provision for credit losses	7,319	6,635	12,001
Accounts written off, net of recoveries	(14,915)	(9,823)	(11,400)
Balance, end of period	22,498	30,094	$ 33,282
Income Taxes
Provision for federal income taxes for REIT entities	0
Deferred tax liabilities, net	$ 265,700	0
Deferred tax assets, net		$ 0