Segment Information (Details) (USD $) In Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010
Segment Reporting Information [Line Items]
Number of customers	more than 6,000 customers		more than 6,000 customers
Revenues	$ 162,410	$ 158,373	$ 326,016	$ 290,004
Operating Income (Loss)	19,121	17,056	73,412	16,803
Depreciation	3,406	2,782	6,770	5,427
General and Administrative Expense	16,314	19,801	38,402	37,498
Amortization of Intangible Assets	9,592	9,915	19,310	18,481
Restructuring charges	439	4,548	981	12,306	21,000
Acquisition-related costs	0	865	0	7,608
Litigation settlement	0	0	(37,500)	0
Supply Chain [Member]
Segment Reporting Information [Line Items]
Segment Reporting Information, Revenue for Reportable Segment	156,916	152,931	316,242	278,164
Operating Income (Loss)	45,562	52,638	95,121	92,542
Depreciation	3,198	2,634	6,395	5,063
Pricing and Revenue Management [Member]
Segment Reporting Information [Line Items]
Segment Reporting Information, Revenue for Reportable Segment	5,494	5,442	9,774	11,840
Operating Income (Loss)	(96)	(453)	(516)	154
Depreciation	208	148	375	364
Unallocated Amount to Segment [Member]
Segment Reporting Information [Line Items]
Operating Income (Loss)	(26,345)	(35,129)	(21,193)	(75,893)
General and Administrative Expense	16,314	19,801	38,402	37,498
Amortization of Intangible Assets	9,592	9,915	19,310	18,481
Restructuring charges	439	4,548	981	12,306
Acquisition-related costs	0	865	0	7,608
Litigation settlement	$ 0	$ 0	$ (37,500)	$ 0