Goodwill and Intangible Assets - Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Accumulated Amortization	$ (42,115)	$ (10,915)
Finite-Lived Intangible Assets, Net	41,715	9,064
Intangible Assets, Gross (Excluding Goodwill)	83,830	19,979
Indefinite-Lived Intangible Assets (Excluding Goodwill)	3,556	3,307
Intangible Assets Arising from Insurance Contracts Acquired in Business Combination [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	42,788	8,975
Finite-Lived Intangible Assets, Accumulated Amortization	(34,335)	(7,867)
Finite-Lived Intangible Assets, Net	8,453	1,108
Customer Relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	34,661	10,284
Finite-Lived Intangible Assets, Accumulated Amortization	(6,669)	(2,784)
Finite-Lived Intangible Assets, Net	$ 27,992	$ 7,500
Finite-Lived Intangible Assets, Remaining Amortization Period	8 years	3 years 8 months
Trade Names
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 6,381	$ 720
Finite-Lived Intangible Assets, Accumulated Amortization	(1,111)	(264)
Finite-Lived Intangible Assets, Net	$ 5,270	$ 456
Finite-Lived Intangible Assets, Remaining Amortization Period	6 years	2 years 1 month