Interim Financial Statements (Details Textuals) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended				3 Months Ended	6 Months Ended
	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011 7.75% senior subordinated notes due 2016 [Member]	Dec. 31, 2006 7.75% senior subordinated notes due 2016 [Member]	Jun. 30, 2010 3.5% senior subordinated convertible notes due 2026 [Member]	Jun. 30, 2010 3.5% senior subordinated convertible notes due 2026 [Member]	Jun. 30, 2011 3.5% senior subordinated convertible notes due 2026 [Member]
Interim Financial Statement (Textuals)
Pre tax gain relating to convertible notes repurchased	$ 422		$ 1,027			$ 422	$ 1,027
Face value of 3.5% senior subordinated convertible notes repurchased						41,548	112,658
Senior subordinated convertible notes due 2026, interest rate	3.50%	3.50%	3.50%	7.75%	7.75%	3.50%	3.50%	3.50%
Interim Financial Statements (Textuals) [Abstract]
Total number of owned and operated franchises		323
Number of owned and operated franchises in US		168
Number of owned and operated franchises outside US		155
Awarded franchises		4
Acquired franchises		3
Disposed franchises		7
Disposed smart centers		4
Aggregate cash purchase price for the assets		44,462
Limited partnership interest in Penske Truck Leasing Co.		9.00%
Business acquisition purchase price allocation assets acquired cash paid		$ 688