Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Revenues	$ 112,329	$ 113,587	$ 91,119	$ 108,508	$ 107,556	$ 108,646	$ 103,542	$ 104,881	$ 425,544	$ 424,625	$ 433,732
Revenue, remaining performance obligation, percentage									100.00%	100.00%
Revenue recognized over time
Disaggregation of Revenue [Line Items]
Revenues									$ 21,479	$ 16,146
Revenue, remaining performance obligation, percentage									5.00%	3.80%
Revenue recognized at a point in time
Disaggregation of Revenue [Line Items]
Revenues									$ 404,065	$ 408,479
Revenue, remaining performance obligation, percentage									95.00%	96.20%