CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash flows from operating activities:
Net income	$ 116,491	$ 102,003
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	7,561	7,939
Amortization of intangibles	37,091	27,739
Amortization of contract acquisition costs	9,485	9,697
Deferred income taxes	(1,032)	(1,368)
Employee share-based compensation expense	6,865	5,940
Loss on early debt extinguishment	0	8,917
Other non-cash items, net	2,829	139
Changes in assets and liabilities, net of effect of acquisitions:
Trade accounts receivable	14,038	19,434
Inventories and supplies	3,924	27
Other current assets	1,268	4,060
Non-current assets	(1,723)	608
Accounts payable	(4,487)	(11,576)
Contract acquisition payments	(14,341)	(5,848)
Other accrued and non-current liabilities	(49,703)	(20,804)
Net cash provided by operating activities	128,266	146,907
Cash flows from investing activities:
Purchases of capital assets	(22,184)	(19,307)
Payments for acquisitions, net of cash acquired	(28,497)	(35,800)
Proceeds from company-owned life insurance policies	3,053	0
Other	2,087	339
Net cash used by investing activities	(45,541)	(54,768)
Cash flows from financing activities:
Proceeds from short-term borrowings	0	75,000
Proceeds from issuing long-term debt	107,000	211,500
Payments on long-term debt, including costs of debt reacquisition	(128,584)	(346,021)
Proceeds from issuing shares under employee plans	4,193	4,135
Excess tax benefit from share-based employee awards	0	1,557
Employee taxes paid for shares withheld	(2,260)	(871)
Payments for common shares repurchased	(29,981)	0
Cash dividends paid to shareholders	(29,446)	(30,043)
Other	(417)	(286)
Net cash used by financing activities	(79,495)	(85,029)
Effect of exchange rate change on cash	3,935	(3,725)
Net change in cash and cash equivalents	7,165	3,385
Cash and cash equivalents, beginning of year	62,427	61,541
Cash and cash equivalents, end of period	$ 69,592	$ 64,926