Supplemental Balance Sheet, Income Statement and Cash Flow Information - Acquisitions of Businesses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Supplemental cash flow information
Cash paid for income taxes	$ 11,383	$ 20,581	$ 34,479
Cash paid for interest, net of capitalized interest	202,803	191,986	184,445
Net change in accounts payable related to capital expenditures	(8,556)	(35,227)	22,920
Net change in assets related to increase in redeemable noncontrolling interest in subsidiary	43,928	142,875
Acquisitions of businesses:
Fair value of assets acquired	48,053	280,709
Goodwill	11,436	5,690
Liabilities assumed	(34,489)	(55,742)
Shares issuance as consideration (non-cash financing activity)		(178,993)
Payments on future consideration			22,278
Cash paid for acquisitions of businesses	25,000	51,664	22,278
Cash and restricted cash acquired in acquisitions of businesses	(4,141)	(63,983)
Cash paid for acquisition of businesses, net of cash acquired	$ (20,859)	$ 12,319	$ (22,278)