Fair Value Measurements - Goodwill and Asset Impairment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill			$ 351,652
Property, plant and equipment and leasehold intangibles, net	$ 2,500	$ 149,900	50,200	$ 152,400
Investment in unconsolidated ventures			33,400	19,700
Goodwill and asset impairment	5,500	368,551	451,966	390,816
Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill	0	205,000	351,700	205,000
Property, plant and equipment and leasehold intangibles, net	2,500	149,900	50,200	152,400
Investment in unconsolidated ventures	0	0	33,400	19,700
Other intangible assets, net	0	13,700	1,700	13,700
Assets held for sale (Note 4)	3,000	0	15,000	0
Goodwill and asset impairment	$ 5,500	$ 368,600	$ 452,000	$ 390,800