Leases (Supplemental cash flow information related to leases) (Details) - USD ($) $ in Thousands	4 Months Ended	8 Months Ended	12 Months Ended
	Dec. 31, 2020	Aug. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating cash flows for operating leases	$ 1,489	$ 3,849	$ 4,034
Financing cash flows for finance leases	1,407	2,757	4,001
Lease liabilities recognized in exchange for new operating lease right of use assets	$ 0	$ 0	$ 5