Income Taxes - Narrative (Details)			3 Months Ended								12 Months Ended
	Oct. 31, 2018	Oct. 31, 2016 $ / shares	Dec. 31, 2018 USD ($) $ / shares	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($) $ / shares	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2018 USD ($) $ / shares	Dec. 31, 2017 USD ($) $ / shares	Dec. 31, 2016 USD ($) $ / shares
Operating Loss Carryforwards [Line Items]
Stock distribution ratio	5	5
Common stock dividend paid in lieu of fractional shares (in dollars per share) | $ / shares			$ 1.48				$ 1.48				$ 1.48	$ 1.48	$ 8.265
Income (loss) before income taxes			$ (833,600,000)	$ (98,908,000)	$ (88,375,000)	$ (37,331,000)	$ 50,957,000	$ 12,263,000	$ (18,874,000)	$ (454,746,000)	$ (1,058,214,000)	$ (410,400,000)	$ (367,284,000)
Tax expense recorded from Tax Cuts and Jobs Act							17,000,000
Income tax expense from discontinued operations											0	0	48,181,000
Net operating loss carryforward			20,559,000				10,720,000				20,559,000	10,720,000	8,784,000
Amount that tax basis of net assets is less than reported amounts			1,400,000,000				$ 1,700,000,000				1,400,000,000	1,700,000,000	2,000,000,000
UK
Operating Loss Carryforwards [Line Items]
Income (loss) before income taxes											11,000,000	4,000,000	4,000,000
QCP
Operating Loss Carryforwards [Line Items]
Share price (in dollars per share) | $ / shares		$ 30.85
TRS
Operating Loss Carryforwards [Line Items]
Income (loss) before income taxes											59,000,000	$ 58,000,000	$ 9,000,000
Net operating loss carryforward			80,000,000								80,000,000
Net operating loss carryforwards subject to expiration			44,000,000								44,000,000
Net operating loss carryforwards not subject to expiration			$ 36,000,000								$ 36,000,000