Held for Sale and Discontinued Operations Financial results for discontinued operations related to DMG (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Goodwill and other asset impairment charges	$ 124,892	$ 3,106	$ 36,196
Valuation adjustment on disposal group	0	316,840	0
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	105,483	(457,038)	(245,372)
DMG - Held for sale | Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net revenues	2,713,059	4,963,792	4,676,213
Expenses	2,543,865	4,962,686	4,634,782
Goodwill and other asset impairment charges	0	41,537	651,659
Valuation adjustment on disposal group	0	316,840	0
Income (loss) from discontinued operations before taxes	169,194	(357,271)	(610,228)
Loss on sale of discontinued operations before taxes	(23,022)	0	0
Income tax expense (benefit)	$ 40,689	$ 99,768	$ (364,856)