Revenue Recognition (Disaggregation of Revenue by Geography) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Disaggregation of Revenue [Line Items]
Revenue	$ 257,124	$ 219,191
United States [Member]
Disaggregation of Revenue [Line Items]
Revenue	214,394	185,327
United Kingdom [Member]
Disaggregation of Revenue [Line Items]
Revenue	27,660	22,305
Other countries [Member]
Disaggregation of Revenue [Line Items]
Revenue	$ 15,070	$ 11,559

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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+ Details