Goodwill, Trade Names, and Other Intangible Assets - Acquired Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 64,372	$ 85,108
Accumulated Amortization	29,541	40,151
Net Carrying Amount	34,831	44,957
Trade names, indefinite-lived	5,900	5,900
Databases
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	30,530	30,530
Accumulated Amortization	15,322	12,269
Net Carrying Amount	15,208	18,261
Customer relationships
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	33,538	49,758
Accumulated Amortization	14,007	26,596
Net Carrying Amount	19,531	23,162
Non-compete agreements
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	304	320
Accumulated Amortization	212	161
Net Carrying Amount	92	159
Trade names
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	0	4,500
Accumulated Amortization	0	1,125
Net Carrying Amount	$ 0	$ 3,375