Retirement benefits (Tables)

12 Months Ended

Dec. 31, 2019

Retirement Benefits [Abstract]

Summary of contribution expense

Our contribution expense was as follows:

			Successor				Predecessor
					Period from		Period from
					March 22, 2017		January 1, 2017
	For the Year Ended December 31,				through		through
	2019		2018		December 31, 2017		March 21, 2017
401(k) contribution expense	$	1,509	$	1,543	$	1,267	$	396