Commitments and Contingent Liabilities (Details) - USD ($) $ in Thousands			1 Months Ended	6 Months Ended
	Jun. 30, 2017	Jul. 26, 2016	Mar. 31, 2015	Jun. 30, 2017
Commitments and Contingent Liabilities
Lease period, minimum				5 years
Lease period, maximum				20 years
Loss Contingencies
Letters of credit outstanding	$ 32,500			$ 32,500
Surety bonds posted	25,600			25,600
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%
PTL
Loss Contingencies
Ownership interest in Penske Truck Leasing Co (as a percent)	23.40%	9.00%
GEC | PTL
Loss Contingencies
Ownership interest in Penske Truck Leasing Co (as a percent)	15.50%
Mitsui and Co
Loss Contingencies
Purchase of ownership interest			20.00%
Mitsui and Co | PTL
Loss Contingencies
Ownership interest in Penske Truck Leasing Co (as a percent)	20.00%
Penske Corporation | PTL
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