Lines of Credit - Additional Information (Detail) (USD $)
3 Months Ended
Mar. 31, 2015
Line of Credit Facility [Line Items]  
Line of credit, pro forma excess borrowing availability for restricted payments and acquisitions to occur without financial covenants $ 250,000,000
Line of credit, minimum borrowing availability for financial maintenance covenants to be applicable 100,000,000
Line of credit, covenant Payment Conditions allow restricted payments and acquisitions to occur without financial covenants as long as the Company has $250.0 million of pro forma excess borrowing availability under the Credit Agreement.
Maximum  
Line of Credit Facility [Line Items]  
Percentage of net orderly liquidation value of lease-fleet to be included in determination of borrowing base 90.00%
LIBOR Loans  
Line of Credit Facility [Line Items]  
Revolving credit facility, margin rate 2.00%
LIBOR Loans | Maximum  
Line of Credit Facility [Line Items]  
Revolving credit facility, margin rate 2.25%
LIBOR Loans | Minimum  
Line of Credit Facility [Line Items]  
Revolving credit facility, margin rate 1.75%
Base Rate Loans  
Line of Credit Facility [Line Items]  
Revolving credit facility, margin rate 1.00%
Base Rate Loans | Maximum  
Line of Credit Facility [Line Items]  
Revolving credit facility, margin rate 1.25%
Base Rate Loans | Minimum  
Line of Credit Facility [Line Items]  
Revolving credit facility, margin rate 0.75%
$1.0 billion ABL Credit Agreement  
Line of Credit Facility [Line Items]  
Credit Agreement, borrowing capacity $ 1,000,000,000
Credit Agreement, term 5 years
Credit Agreement, maturity date Feb. 22, 2017