Supplemental Balance Sheet, Income Statement and Cash Flow Information - Reclass Accumulated Other (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Unrealized (gains) losses on available-for-sale securities that were reclassified from net income
Investment income (loss)	$ 465	$ 721
Interest expense	61,386	56,518
General and administrative expenses	74,571	63,409
Other expense (income), net	14,089	13,510
Income (loss) from continuing operations before income taxes	(120,042)	(173,237)
Income tax expense (benefit)	23,545	(25,609)
Net income (loss)	(143,662)	(148,067)
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	140	153
General and administrative expenses	54	50
Income (loss) from continuing operations before income taxes	(194)	(203)
Income tax expense (benefit)	(43)	(79)
Net income (loss)	$ (151)	$ (124)