Segment Information - Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segments Information
Assets	$ 2,561,477	$ 1,455,777	$ 1,332,585
Adjustment
Segments Information
Assets		(107,988)	(5,520)
Operating Segments
Segments Information
Assets	2,258,830	1,381,396	1,277,460
Corporate, Non-Segment
Segments Information
Assets	302,647	74,381	55,125
Consumer services and plans | Operating Segments
Segments Information
Assets	180,295	152,689	139,064
Retail | Operating Segments
Segments Information
Assets	$ 2,078,535	1,228,707	1,138,396
Retail | Operating Segments | Adjustment
Segments Information
Assets		$ (5,300)	$ 5,500