Acquisitions (Details) $ in Thousands, £ in Millions, $ in Millions	1 Months Ended						3 Months Ended		9 Months Ended
	Aug. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2018 CAD ($)	Apr. 30, 2018 USD ($)	Feb. 28, 2018 USD ($)	Feb. 28, 2018 GBP (£)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Dec. 18, 2018	Dec. 17, 2018
Business Acquisition [Line Items]
Acquisition									$ 6,551
Measurement period adjustments									(83)
Acquisition related costs							$ 100	$ 200	300	$ 1,900
National Tax Search LLC
Business Acquisition [Line Items]
Consideration transferred	$ 15,000
Contingent consideration	7,500
Contract liabilities	1,800
Goodwill deductible amount for tax purposes	6,600
National Tax Search LLC | Technology-Based Intangible Assets
Business Acquisition [Line Items]
Intangible assets acquired	$ 3,200
Estimated average life in years	7 years
National Tax Search LLC | Client lists
Business Acquisition [Line Items]
Intangible assets acquired	$ 4,600
Estimated average life in years	10 years
National Tax Search LLC | Trademarks
Business Acquisition [Line Items]
Intangible assets acquired	$ 900
Estimated average life in years	7 years
National Tax Search LLC | Non-compete agreements
Business Acquisition [Line Items]
Intangible assets acquired	$ 300
Estimated average life in years	5 years
Symbility
Business Acquisition [Line Items]
Remaining equity interest acquired											72.00%
Consideration transferred		$ 80,000	$ 107.1
Deferred tax liability acquired							5,300		5,300
Ownership percentage												28.00%
Step acquisition remeasurement gain		13,300
Measurement period adjustments									(200)
Symbility | Technology-Based Intangible Assets
Business Acquisition [Line Items]
Intangible assets acquired							14,900		$ 14,900
Estimated average life in years									8 years
Symbility | Client lists
Business Acquisition [Line Items]
Intangible assets acquired							6,400		$ 6,400
Estimated average life in years									12 years
Symbility | Trademarks
Business Acquisition [Line Items]
Intangible assets acquired							1,200		$ 1,200
Estimated average life in years									4 years
HomeVisit
Business Acquisition [Line Items]
Consideration transferred		$ 12,700
Measurement period adjustments									$ 100
HomeVisit | Client lists
Business Acquisition [Line Items]
Intangible assets acquired							900		$ 900
Estimated average life in years									11 years
HomeVisit | Trademarks
Business Acquisition [Line Items]
Intangible assets acquired							200		$ 200
Estimated average life in years									3 years
HomeVisit | Non-compete agreements
Business Acquisition [Line Items]
Intangible assets acquired							1,400		$ 1,400
Estimated average life in years									5 years
a la mode
Business Acquisition [Line Items]
Consideration transferred				$ 120,000
Contract liabilities							7,500		$ 7,500
Goodwill deductible amount for tax purposes							61,400		61,400
a la mode | Technology-Based Intangible Assets
Business Acquisition [Line Items]
Intangible assets acquired							15,800		$ 15,800
Estimated average life in years									7 years
a la mode | Client lists
Business Acquisition [Line Items]
Intangible assets acquired							32,500		$ 32,500
Estimated average life in years									13 years
a la mode | Non-compete agreements
Business Acquisition [Line Items]
Intangible assets acquired							5,700		$ 5,700
Estimated average life in years									5 years
a la mode | Trade names
Business Acquisition [Line Items]
Intangible assets acquired							$ 9,000		$ 9,000
Estimated average life in years									8 years
eTech
Business Acquisition [Line Items]
Consideration transferred					$ 21,000	£ 15.0
Deferred tax liability acquired					1,600
eTech | Technology-Based Intangible Assets
Business Acquisition [Line Items]
Intangible assets acquired					$ 7,000
Estimated average life in years					5 years	5 years
eTech | Client lists
Business Acquisition [Line Items]
Intangible assets acquired					$ 1,700
Estimated average life in years					9 years	9 years
UWS
Business Acquisition [Line Items]
Acquisition									$ 6,551
Measurement period adjustments									0
UWS | a la mode
Business Acquisition [Line Items]
Acquisition									63,600
PIRM
Business Acquisition [Line Items]
Acquisition									0
Measurement period adjustments									(83)
PIRM | Symbility
Business Acquisition [Line Items]
Acquisition									75,600
PIRM | HomeVisit
Business Acquisition [Line Items]
Acquisition									$ 10,400
PIRM | eTech
Business Acquisition [Line Items]
Acquisition					$ 14,100