Goodwill, Trade Names, and Other Intangible Assets - Acquired Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Oct. 01, 2018
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 85,108	$ 89,487
Accumulated Amortization	40,151	34,305
Net Carrying Amount	44,957	55,182
Trade names, indefinite-lived	5,900	20,402
Databases
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	30,530	30,530
Accumulated Amortization	12,269	9,216
Net Carrying Amount	18,261	21,314
Customer relationships
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	49,758	49,758
Accumulated Amortization	26,596	23,296
Net Carrying Amount	23,162	26,462
Non-compete agreements
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	320	320
Accumulated Amortization	161	97
Net Carrying Amount	159	223
Trade names
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	4,500	8,879
Accumulated Amortization	1,125	1,696
Net Carrying Amount	$ 3,375	$ 7,183	$ 1,100