Revenue - Change in contract balances (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Contract assets:
Contract assets, beginning of period	$ 12,695
Decreases due to cash received	(10,627)
Changes to the contract assets at the beginning of the period as a result of changes in estimates	2,915
Changes during the year, net of reclassifications to receivables	17,060
Contract assets, end of period	22,043
Contract liabilities:
Contract liabilities, beginning of period	2,191	$ 1,982
Revenue recognized that was included in the contract liabilities balance at the beginning of the period	(1,810)	$ (1,243)
Increases due to cash received, excluding amounts recognized as revenue during the period	2,521
Contract liabilities, end of period	$ 2,902