Supplemental Balance Sheet and Income Statement Information - Reclass Accumulated Other (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Unrealized (gains) losses on available-for-sale securities that were reclassified from net income
Interest expense	$ 52,352	$ 61,386
General and administrative expenses	68,167	74,571
Income (loss) from continuing operations before income taxes	(73,577)	(120,042)
Income tax expense (benefit)	29,799	23,545
Net income (loss)	(103,533)	(143,662)
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	140
General and administrative expenses	54	54
Income (loss) from continuing operations before income taxes	(194)	(194)
Income tax expense (benefit)	(46)	(43)
Net income (loss)	$ (148)	$ (151)