Segments Information - Segment Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segments Information
Total segment income	$ 136,750	$ 103,351	$ 206,507	$ 159,392
Selling, general, and administrative expense	(228,444)	(190,323)	(403,934)	(350,711)
Depreciation and amortization	(7,584)	(6,034)	(14,437)	(11,925)
Other interest expense, net	(10,557)	(12,577)	(19,961)	(25,325)
Other income (expense), net		(2)	17	(2)
Income before income taxes	119,606	85,385	174,674	123,536
Operating Segments
Segments Information
Total segment income	141,230	104,707	213,479	162,117
Depreciation and amortization	(7,469)	(6,034)	(14,322)	(11,925)
Other interest expense, net	(1,362)	(1,380)	(2,956)	(2,776)
Corporate, Non-Segment
Segments Information
Selling, general, and administrative expense	(3,483)	(711)	(4,424)	(1,329)
Depreciation and amortization	(115)		(115)
Other interest expense, net	(9,195)	(11,197)	(17,005)	(22,549)
Consumer services and plans | Operating Segments
Segments Information
Total segment income	23,959	22,503	50,212	44,101
Depreciation and amortization	(1,005)	(932)	(2,001)	(1,851)
Other interest expense, net	(2)	(4)	(4)	(8)
Retail | Operating Segments
Segments Information
Total segment income	117,271	82,204	163,267	118,016
Depreciation and amortization	(6,464)	(5,102)	(12,321)	(10,074)
Other interest expense, net	$ (1,360)	$ (1,376)	$ (2,952)	$ (2,768)