Commitments and Contingent Liabilities (Details) - USD ($) $ in Thousands		1 Months Ended	9 Months Ended
	Sep. 30, 2016	Mar. 31, 2015	Sep. 30, 2016
Commitments and Contingent Liabilities
Lease period, minimum			5 years
Lease period, maximum			20 years
Loss Contingencies
Ownership interest in Penske Truck Leasing Co (as a percent)	23.40%
Letters of credit outstanding	$ 33,100		$ 33,100
Surety bonds posted	12,600		12,600
Holdings | Holdings Bond
Loss Contingencies
Senior unsecured notes issued	$ 700,000		$ 700,000
Senior subordinated convertible notes, interest rate (as a percent)	3.80%		3.80%
Percentage of interest and principal due to the co-obligor as a result of the change in ownership and subsequent relief of debt obligation		50.10%
Percentage of expenses relating to the debt obligation due to the co-obligor as a result of the change in ownership and subsequent relief of debt obligation		100.00%
Penske Truck Leasing Co., L.P.
Loss Contingencies
Ownership interest in Penske Truck Leasing Co (as a percent)	23.40%
GEC
Loss Contingencies
Ownership interest in Penske Truck Leasing Co (as a percent)	15.50%
Mitsui and Co
Loss Contingencies
Ownership interest in Penske Truck Leasing Co (as a percent)	20.00%
Purchase of ownership interest		20.00%
Penske Corporation
Loss Contingencies
Ownership interest in Penske Truck Leasing Co (as a percent)	41.10%
Guarantee of Indebtedness of Others | GEC
Loss Contingencies
Percentage of interest agreed to indemnify if GEC required to make any payments of principal or interest	9.00%		9.00%
Annual fee pay for acting as co-obligor	$ 950		$ 950
Value of principal repayment included in maximum amount of Company's potential obligations	$ 63,100		$ 63,100