Acquisitions (Details) $ in Thousands, $ in Thousands, £ in Millions	1 Months Ended					6 Months Ended
	Dec. 31, 2018 USD ($)	Dec. 31, 2018 CAD ($)	Apr. 30, 2018 USD ($)	Feb. 28, 2018 USD ($)	Feb. 28, 2018 GBP (£)	Jun. 30, 2019 USD ($)	Dec. 18, 2018	Dec. 17, 2018
Business Acquisition [Line Items]
Measurement period adjustments						$ (124)
Symbility
Business Acquisition [Line Items]
Remaining equity interest acquired							72.00%
Consideration transferred	$ 80,000	$ 107,100
Deferred tax liability acquired						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
Estimated average life in years						8 years
Symbility | Client lists
Business Acquisition [Line Items]
Intangible assets acquired						$ 6,400
Estimated average life in years						12 years
Symbility | Trademarks
Business Acquisition [Line Items]
Intangible assets acquired						$ 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
Estimated average life in years						11 years
HomeVisit | Trademarks
Business Acquisition [Line Items]
Intangible assets acquired						$ 200
Estimated average life in years						2 years 6 months
HomeVisit | Non-compete agreements
Business Acquisition [Line Items]
Intangible assets acquired						$ 1,400
Estimated average life in years						5 years
a la mode
Business Acquisition [Line Items]
Consideration transferred			$ 120,000
Contract liabilities						$ 7,500
Goodwill deductible amount for tax purposes						61,400
a la mode | Technology-Based Intangible Assets
Business Acquisition [Line Items]
Intangible assets acquired						$ 15,800
Estimated average life in years						7 years
a la mode | Client lists
Business Acquisition [Line Items]
Intangible assets acquired						$ 32,500
Estimated average life in years						13 years
a la mode | Non-compete agreements
Business Acquisition [Line Items]
Intangible assets acquired						$ 5,700
Estimated average life in years						5 years
a la mode | Trade names
Business Acquisition [Line Items]
Intangible assets acquired						$ 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]
Measurement period adjustments						$ 0
UWS | a la mode
Business Acquisition [Line Items]
Acquisitions						63,600
PIRM
Business Acquisition [Line Items]
Measurement period adjustments						(124)
PIRM | Symbility
Business Acquisition [Line Items]
Acquisitions						75,600
PIRM | HomeVisit
Business Acquisition [Line Items]
Acquisitions						$ 10,300
PIRM | eTech
Business Acquisition [Line Items]
Acquisitions				$ 14,100