Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Operating activities
Net income	$ 192,831	$ 163,658
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	15,096	9,673
Stock-based compensation	30,500	18,299
Provision for losses on accounts receivable	13,022	12,283
Amortization of deferred financing costs and discounts	3,517	1,062
Amortization of intangible assets	80,186	36,482
Amortization of premium on receivables	1,627	1,630
Deferred income taxes	(40,894)	2,032
Equity method investment loss	7,818	1,489
Other non-cash operating expenses	(772)
Changes in operating assets and liabilities (net of acquisitions):
Restricted cash	5,790	2,092
Accounts receivable	(233,528)	(197,667)
Prepaid expenses and other current assets	24	(8,285)
Other assets	(2,961)	(389)
Excess tax benefits related to stock-based compensation	(9,639)	(18,634)
Accounts payable, accrued expenses, income taxes and deferred revenue	135,795	133,996
Net cash provided by operating activities	198,412	157,721
Investing activities
Acquisitions, net of cash acquired	(7,954)	(189,850)
Purchases of property and equipment	(16,234)	(11,552)
Net cash used in investing activities	(24,188)	(201,402)
Financing activities
Excess tax benefits related to stock-based compensation	9,639	18,634
Proceeds from issuance of common stock	7,105	8,277
Borrowings on securitization facility, net	89,000	75,400
Deferred financing costs paid		(546)
Principal payments on notes payable	(51,750)	(13,750)
Borrowings from revolver - A Facility		142,330
Payments on revolver - A Facility	(276,818)	(262,377)
Payments on foreign revolver - B Facility		(7,337)
Borrowings from swing line of credit, net	9,441	41,522
Payment of contingent consideration	(39,808)
Other	(145)	(371)
Net cash (used in) provided by financing activities	(253,336)	1,782
Effect of foreign currency exchange rates on cash	(13,782)	1,436
Net decrease in cash and cash equivalents	(92,894)	(40,463)
Cash and cash equivalents, beginning of period	477,069	338,105
Cash and cash equivalents, end of period	384,175	297,642
Supplemental cash flow information
Cash paid for interest	38,883	12,797
Cash paid for income taxes	$ 30,234	$ 52,697