Segment Information Gross Profit by Segment and Category (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Gross Profit by Category [Line Items]
Gross Profit	$ 328,067	$ 315,377	$ 637,518	$ 635,479
North America [Member]
Gross Profit by Category [Line Items]
Gross Profit	233,860	217,174	454,797	433,117
International [Member]
Gross Profit by Category [Line Items]
Gross Profit	94,207	98,203	182,721	202,362
Local [Member] | North America [Member]
Gross Profit by Category [Line Items]
Gross Profit	179,609	158,812	348,951	322,830
Local [Member] | International [Member]
Gross Profit by Category [Line Items]
Gross Profit	62,303	62,970	121,497	127,191
Goods [Member] | North America [Member] | Third party and other [Member]
Gross Profit by Category [Line Items]
Gross Profit	3,207	2,019	4,514	3,692
Goods [Member] | North America [Member] | Direct [Member]
Gross Profit by Category [Line Items]
Gross Profit	33,289	40,009	68,412	74,549
Goods [Member] | International [Member] | Third party and other [Member]
Gross Profit by Category [Line Items]
Gross Profit	4,506	5,848	8,161	17,551
Goods [Member] | International [Member] | Direct [Member]
Gross Profit by Category [Line Items]
Gross Profit	17,402	18,901	33,031	35,894
Travel [Member] | North America [Member]
Gross Profit by Category [Line Items]
Gross Profit	17,755	16,334	32,920	32,046
Travel [Member] | International [Member]
Gross Profit by Category [Line Items]
Gross Profit	$ 9,996	$ 10,484	$ 20,032	$ 21,726