Related Party Transactions (Details 6) (USD $) In Thousands	9 Months Ended
	Sep. 30, 2010
GM [Member]
Expenses incurred with General Motors Company and American Honda
Total	$ 48,257
GM [Member] | Sales and marketing [Member]
Expenses incurred with General Motors Company and American Honda
Total	13,374
GM [Member] | Revenue share and royalties [Member]
Expenses incurred with General Motors Company and American Honda
Total	15,823
GM [Member] | Subscriber acquisition costs [Member]
Expenses incurred with General Motors Company and American Honda
Total	17,514
GM [Member] | Customer service and billing [Member]
Expenses incurred with General Motors Company and American Honda
Total	125
GM [Member] | Interest expense, net of amounts capitalized [Member]
Expenses incurred with General Motors Company and American Honda
Total	1,421
American Honda [Member]
Expenses incurred with General Motors Company and American Honda
Total	5,136
American Honda [Member] | Sales and marketing [Member]
Expenses incurred with General Motors Company and American Honda
Total	0
American Honda [Member] | Revenue share and royalties [Member]
Expenses incurred with General Motors Company and American Honda
Total	3,167
American Honda [Member] | Subscriber acquisition costs [Member]
Expenses incurred with General Motors Company and American Honda
Total	1,969
American Honda [Member] | Customer service and billing [Member]
Expenses incurred with General Motors Company and American Honda
Total	0
American Honda [Member] | Interest expense, net of amounts capitalized [Member]
Expenses incurred with General Motors Company and American Honda
Total	$ 0