Summary of Significant Accounting Policies (Narrative) (Detail) (USD $)	1 Months Ended		12 Months Ended					1 Months Ended					12 Months Ended
	Feb. 04, 2013	Nov. 29, 2010	Dec. 31, 2012 M Y D		Dec. 31, 2011		Dec. 31, 2010	Dec. 20, 2010 IPO [Member]	Jun. 30, 2011 2005 Facility [Member]	Jun. 30, 2011 CCS Credit Facility [Member]	Nov. 30, 2012 New Credit Facility [Member]	Jun. 30, 2011 New Credit Facility [Member]	Dec. 31, 2012 Maximum [Member]	Dec. 31, 2012 Minimum [Member]
Significant Accounting Policies [Line Items]
Cost of sales for equipment sold			$ 4,700,000
Customer payment terms (in days)			14
Maximum allocation period (in year)			1
Capitalized computer software costs			10,600,000		6,500,000		4,800,000
Capitalized computer software amortization expense			5,700,000		4,100,000		3,900,000
Minimum percentage of likelihood required to recognize uncertain income tax position			50.00%
Maturity of cash equivalent, max (in months)			3
Foreign exchange gains recognized					600,000		500,000
Foreign exchange loss recognized			400,000
Options granted have vesting range													6 years	1 year
Wrote-off deferred debt issuance costs									1,700,000	1,000,000
Debt issuance costs											3,000,000	7,200,000
Net deferred financing costs			8,100,000		6,600,000
Securitized accounts receivable facility			500,000,000
Maximum Undivided Ownership Interest Pooled Accounts Receivable Amount Sold			500,000,000
Impact on total assets of adoption of SFAS 156							218,000,000
Impact on total liabilities of adoption of SFAS 156							218,000,000
Impact on cash flows of adoption of SFAS 156							218,000,000
Deferred financing fees	600,000
Short-term debt outstanding			298,000,000	[1]	280,000,000	[1]
Premium on purchased receivables			19,700,000		23,000,000
Advertising expense			11,500,000		8,900,000		8,200,000
Common stock, shares issued			116,772,324		113,741,883			430,961
Net proceeds from initial public offering							9,560,000	9,560,000
Common shares sold by selling shareholders in initial public offering								14,145,289
Convertible preferred stock			0		0			43,575,148
Cash dividends received							1,488,000	7,600,000
Compensation expense								$ 23,000,000
Shares of restricted stock and stock options								1,930,972
Stock split ratio		Two and one-half for one

[1] The Company is party to a receivables purchase agreement (Securitization Facility) that was amended and restated for the fourth time as of October 29, 2007 and which has been amended eight times since then to add or remove purchasers, extend the facility termination date and remove all financial covenants. The current purchase limit under the Securitization Facility is $500 million. The Securitization Facility was amended for the eighth time on February 4, 2013 to extend the facility termination date to February 3, 2014. There is a program fee equal to the Commercial Paper Rate of 0.24%, plus 0.75% and 0.24% plus 0.675% as of December 31, 2012 and February 4, 2013, respectively. The unused facility fee is payable at a rate of 0.35% per annum as of December 31, 2012 and 0.30% per annum as of February 4, 2013. The Securitization Facility provides for certain termination events, which includes nonpayment, upon the occurrence of which the administrator may declare the facility termination date to have occurred, may exercise certain enforcement rights with respect to the receivables, and may appoint a successor servicer, among other things.