Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	12 Months Ended			1 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Nov. 30, 2014	Nov. 14, 2014
Significant Accounting Policies [Line Items]
Cost of sales for equipment sold	$ 15,100,000	$ 9,300,000
Customer payment terms (in days)	14 days
Maximum allocation period (in year)	1 year
Capitalized computer software costs	17,700,000	12,800,000	10,600,000
Capitalized computer software amortization expense	9,200,000	7,300,000	5,700,000
Minimum percentage of likelihood required to recognize uncertain income tax position	50.00%
Maturity of cash equivalent, max (in months)	3 months
Foreign exchange gain (loss) recognized	1,400,000	(400,000)	(400,000)
Net deferred financing costs	23,200,000	6,800,000
Securitized accounts receivable facility	1,200,000,000
Maximum undivided ownership interest pooled accounts receivable amount sold	1,200,000,000
Deferred financing fees					3,100,000
Short-term debt outstanding	675,000,000	349,000,000
Premium on purchased receivables	13,200,000	16,400,000
Advertising expense	14,400,000	12,300,000	11,500,000
New Credit Facility [Member]
Significant Accounting Policies [Line Items]
Debt issuance costs				15,800,000
Debt issuance costs capitalized				$ 9,200,000
Minimum [Member]
Significant Accounting Policies [Line Items]
Options granted have vesting range	1 year
Maximum [Member]
Significant Accounting Policies [Line Items]
Options granted have vesting range	6 years