Revenue (Tables)

12 Months Ended

Dec. 31, 2021

Revenue from Contract with Customer [Abstract]

Contract with Customer, Asset and Liability

The following table presents the ending and beginning balances of costs in excess of billings, billings in excess of cost and unearned revenue, respectively, as of December 31, (in thousands):

	2021		2020		2019
Costs in excess of billings	$	54,437	$	26,915	$	20,607
Billings in excess of cost	(46,711)		(34,702)		(47,598)
Unearned revenue	(3,681)		(21,325)		(15,389)