Revenues (Tables)

12 Months Ended

Dec. 31, 2018

Revenue from Contract with Customer [Abstract]

Contract with Customer, Asset and Liability

A summary of significant net changes in the contract assets and the contract liabilities balances during the period is as follows:

	2018
	Net contract liabilities, less contract assets
	(in thousands)
Beginning balance, January 1	$	59,808
Changes due to business combination	36,936
Revenues recognized from beginning contract liability	(32,821		)
Increases due to amounts collected or due	282,016
Revenues recognized from current period increases	(241,510		)
Other	(2,299		)
Ending balance, December 31	$	102,130