Debt (Details Textual) (USD $)	1 Months Ended			3 Months Ended		6 Months Ended	9 Months Ended						1 Months Ended	6 Months Ended		1 Months Ended			9 Months Ended
	Sep. 30, 2012		Apr. 30, 2012	Sep. 30, 2012		Jun. 30, 2012	Sep. 30, 2012		Sep. 30, 2011	May 08, 2012	Apr. 10, 2012	Dec. 31, 2011	Sep. 30, 2012 2011 Senior Secured Notes [Member]	Mar. 31, 2012 2011 Senior Secured Notes [Member]	May 08, 2012 2011 Senior Secured Notes [Member]	Sep. 30, 2012 2010 Senior Secured Notes [Member]	Sep. 30, 2012 Propel Facility [Member]	May 08, 2012 Propel Facility [Member]	Sep. 30, 2012 Minimum [Member]	Sep. 30, 2012 Maximum [Member]	Sep. 30, 2012 Computer Equipment [Member]
Debt Instrument [Line Items]
Loan fees and other loan costs	$ 23,068,000			$ 23,068,000			$ 23,068,000					$ 11,968,000			$ 900,000		$ 700,000
Basis spread on variable rate, One																			3.50%	4.00%
Basis spread on variable rate, Two																			2.50%	3.00%
Proceeds from senior secured notes	75,000,000								25,000,000				25,000,000			50,000,000
Senior secured notes, stated percentage													7.375%			7.75%
Senior secured notes, maturity date													2018			2017
Senior secured notes, periodic principal repayment													1,250,000			2,500,000
Senior secured notes, date of first required payment													May 10, 2013			Dec. 17, 2012
Capital lease obligations	7,780,000			7,780,000			7,780,000					8,950,000									7,500,000
Interest at Propels option at LIBOR, plus a spread																			3.00%	3.75%
Interest at Propels option at Prime, plus a spread																			0.00%	0.75%
Frequency of repayment, Senior Secured Notes														Quarterly
Weighted average interest rate																	3.54%	3.56%
Revolving credit facility, amount outstanding	410,000,000			410,000,000			410,000,000										122,400,000
Maximum borrowing capacity										555,500,000	410,500,000
Debt (Textual) [Abstract]
Line of credit facility borrowing capacity description							A borrowing base equal to (1) The lesser of (i) 30% - 35% (depending, as defined in the amendment, on the Company’s trailing 12-month cost per dollar collected) of eligible estimated remaining collections, initially set at 33%, and (ii) The product of the net book value of all receivable portfolios acquired on or after January 1, 2005 multiplied by 95%, minus (2) The aggregate principal amount outstanding of the senior secured notes
Percentage to be added to base rate for alternate base rate							0.50%
Percentage to be added to adjusted base rate for alternate base rate							1.00%
Debt instrument base rate period							1 month
Percentage of eligible estimated remaining collections							33.00%
Percentage of multiplying factor							95.00%
Percentage of acquisitions excluded							50.00%
Annual capital expenditure limit	12,500,000			12,500,000			12,500,000
Repurchase of common stock							50,000,000
Annual rental expense limit	12,500,000			12,500,000			12,500,000
Outstanding capital lease limit	12,500,000	[1]		12,500,000	[1]		12,500,000	[1]
Acquisition limit	100,000,000			100,000,000			100,000,000
Revolving credit facility, interest rate				4.16%			4.13%
Increased the aggregate revolving loan commitment current borrowing	145,000,000			145,000,000			145,000,000
Revolving credit facility, description of variable rate basis							Interest at a floating rate equal to, at the Company’s option, either: (1) Reserve adjusted LIBOR, plus a spread that ranges from 350 to 400 basis points, depending on the Company’s cash flow leverage ratio; or (2) Alternate Base Rate (“ABR”), plus a spread that ranges from 250 to 300 basis points, depending on the Company’s cash flow leverage ratio. ABR, as defined in the agreement, means the highest of (i) The rate of interest publicly announced by SunTrust Bank as its prime rate in effect at its principal office in Atlanta, Georgia, (ii) The federal funds effective rate from time to time, plus 0.5% and (iii) Reserved adjusted LIBOR for a one month interest period on the applicable date, plus 1.0%;
Additional loan borrowed			145,000,000
Sub-limits for swingline loans and letter of credit	10,000,000			10,000,000			10,000,000
Revolving credit facility, accordion feature											100,000,000
Debt instrument description of discount rate							The discount rate used to determine the present value is 50 basis points over the then current Treasury Rate corresponding to the remaining average life
Capital lease obligations, maximum percentage							7.70%
Capital lease obligations, minimum percentage							0.00%
Financing acquisition through syndicated loan facility	160,000,000			160,000,000			160,000,000
Borrowing base of the face value of the tax lien collateralized notes	90.00%			90.00%			90.00%
Propel Facility, accordion feature	40,000,000			40,000,000			40,000,000
Maximum Borrowing Capacity including Accordion Facility After Amendment										$ 655,500,000
Propel Facility, Term of Facility						3 years

[1]