Acquisitions - Narrative (Details) - USD ($) $ in Thousands			3 Months Ended
	Jan. 02, 2019	Dec. 10, 2018	Mar. 31, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Goodwill			$ 57,483	$ 47,396
Benefit Consultants Group Inc.
Business Acquisition [Line Items]
Transaction value	$ 25,000
Finite-lived intangible assets acquired	16,200
Goodwill	$ 10,100
NTA Life Enterprises
Business Acquisition [Line Items]
Transaction value		$ 405,000
Minimum | Benefit Consultants Group Inc.
Business Acquisition [Line Items]
Acquired finite-lived intangible assets, useful lives			10 years
Maximum | Benefit Consultants Group Inc.
Business Acquisition [Line Items]
Acquired finite-lived intangible assets, useful lives			16 years