Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Cash flows from operating activities:
Net income	$ 262,006	$ 203,657
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of fixed assets	53,070	41,499
Amortization of intangible assets	42,953	28,544
Amortization of debt issuance costs and original issue discount	10,634	1,322
Allowance for doubtful accounts	456	347
KSOP compensation expense	7,969	7,703
Stock based compensation	19,047	11,057
Gain on derivative instruments	(85,187)	0
Gain on sale of discontinued operations	0	(65,410)
Realized gain on available-for-sale securities, net	(14)	(115)
Deferred income taxes	(7,390)	(3,519)
(Gain) loss on disposal of fixed assets	(3)	735
Excess tax benefits from exercised stock options and restricted stock awards	(8,419)	(6,094)
Changes in assets and liabilities, net of effects from acquisitions:
Accounts receivable	37,981	(12,186)
Prepaid expenses and other assets	9,747	(13,593)
Income taxes	11,858	44,808
Accounts payable and accrued liabilities	(27,393)	(26,674)
Fees received in advance	38,305	81,666
Pension and postretirement benefits	(7,129)	(6,064)
Other liabilities	(2,990)	(848)
Net cash provided by operating activities	355,501	286,835
Cash flows from investing activities:
Acquisitions, net of cash acquired of $35,398 and $0, respectively	(2,811,759)	(4,001)
Purchase of non-controlling interest in non-public companies	(101)	(5,000)
Proceeds from sale of discontinued operations	0	155,000
Escrow funding associated with acquisition	(78,694)	0
Proceeds from the settlement of derivative instruments	85,187	0
Capital expenditures	(60,092)	(75,764)
Purchases of available-for-sale securities	(29)	(32)
Proceeds from sales and maturities of available-for-sale securities	230	281
Net cash (used in) provided by investing activities	(2,865,258)	70,484
Cash flows from financing activities:
Proceeds from issuance of long-term debt, net of original issue discount	1,243,966	0
Proceeds of short-term debt, net	30,000	0
Proceeds from issuance of short-term debt with original maturities greater than three months	830,000	0
Repayment of current portion of long-term debt	(170,000)	0
Repayment of long-term debt	(50,000)	0
Payment of debt issuance costs	(23,053)	0
Repurchases of common stock	0	(122,120)
Excess tax benefits from exercised stock options and restricted stock awards	8,419	6,094
Proceeds from stock options exercised	18,103	14,923
Proceeds from issuance of stock as part of a public offering	720,848	0
Net share settlement of restricted stock awards	(2,350)	(1,234)
Other financing activities, net	(2,569)	(2,095)
Net cash provided by (used in) financing activities	2,603,364	(104,432)
Effect of exchange rate changes	12,525	760
Increase in cash and cash equivalents	106,132	253,647
Cash and cash equivalents, beginning of period	39,359	165,801
Cash and cash equivalents, end of period	145,491	419,448
Supplemental disclosures:
Taxes paid	87,914	82,624
Interest paid	37,977	34,002
Noncash investing and financing activities:
Tenant improvement included in other liabilities	448	8,859
Capital lease obligations	905	1,274
Capital expenditures included in accounts payable and accrued liabilities	$ 4,658	$ 1,247