Goodwill and Intangible Assets - Change in Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Goodwill
Balance	$ 153,105	$ 112,940
Acquisitions	195,282	40,165
Balance	348,387	153,105
Consumer services and plans
Goodwill
Balance	49,944	49,944
Balance	49,944	49,944
Retail
Goodwill
Balance	103,161	62,996
Acquisitions	195,282	40,165
Balance	$ 298,443	$ 103,161