COMBINED STATEMENTS OF EQUITY - 9 months ended Sep. 30, 2017 - USD ($) $ in Thousands	Total	Parent Net Investment	Accumulated Other Comprehensive (Loss) Income	Noncontrolling Interest
Beginning balance at Dec. 31, 2016	$ 800,124	$ 1,057,694	$ (400,063)	$ 142,493
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	107,209	96,642		10,567
Actuarially Determined Long-Term Liability Adjustments (Net of ($5,679) Tax)	9,855		9,889	(34)
Comprehensive Income	117,064	96,642	9,889	10,533
Distributions to Noncontrolling Interest	(16,403)			(16,403)
Amortization of Stock/Unit-Based Compensation Awards	15,074	11,284		3,790
Treasury Stock Activity	(1,009)			(1,009)
Net Parent Distributions	(117,884)	(117,884)
Ending balance at Sep. 30, 2017	$ 796,966	$ 1,047,736	$ (390,174)	$ 139,404