Goodwill and Intangible Assets - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Feb. 23, 2017	Oct. 31, 2016
Goodwill [Line Items]
Goodwill	$ 17,648	$ 13,823	$ 11,810
Amortization expense relating to intangible assets	3,634	1,832	2,500
Projected amortization expense 2018	3,400
Projected amortization expense 2019	3,500
Projected amortization expense 2020	3,300
Projected amortization expense 2021	1,700
Projected amortization expense 2022	900
Recovery Audit Services – Americas
Goodwill [Line Items]
Goodwill	13,440	10,755	10,755
Adjacent Services
Goodwill [Line Items]
Goodwill	2,528	2,388	$ 242
C&CA
Goodwill [Line Items]
Goodwill				$ 3,554
C&CA | Recovery Audit Services – Americas
Goodwill [Line Items]
Goodwill	$ 3,600
Lavante
Goodwill [Line Items]
Goodwill					$ 2,286
Lavante | Adjacent Services
Goodwill [Line Items]
Goodwill		$ 2,100