Supplemental Balance Sheet and Income Statement Information - Reclass Accumulated Other (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Unrealized (gains) losses on available-for-sale securities that were reclassified from net income
Investment income (loss)	$ (3,164)	$ (886)	$ (2,699)	$ (165)
Interest expense	60,592	54,688	121,978	111,206
General and administrative expenses	67,823	63,695	142,394	127,104
Other expense (income), net	77,601	10,104	91,690	23,614
Income (loss) from continuing operations before income taxes	(171,937)	(134,972)	(291,979)	(308,209)
Income tax expense (benefit)	23,278	(19,496)	46,823	(45,105)
Net income (loss)	(195,799)	(130,980)	(339,461)	(279,047)
Reclassification adjustment for (gains)/losses included in net income (loss)
Unrealized (gains) losses on available-for-sale securities that were reclassified from net income
Interest expense	142	153	282	306
General and administrative expenses	54	50	108	100
Other expense (income), net		1,341		1,341
Income (loss) from continuing operations before income taxes	(196)	(1,544)	(390)	(1,747)
Income tax expense (benefit)	(48)	(78)	(91)	(157)
Net income (loss)	$ (148)	$ (1,466)	$ (299)	$ (1,590)