UNAUDITED CONDENSED COMBINED STATEMENTS OF CHANGES IN NET PARENT INVESTMENT - Predecessor - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of the period	$ 73,942	$ 74,258
Net income	36,222	37,804
Net transfers to Parent	(32,018)	(39,113)
Balance, end of the period	$ 78,146	$ 72,949