Consolidated Condensed Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash flows from operating activities:
Net income	$ 263,248	$ 210,308
Adjustments to reconcile net income to net cash provided by operating activities (See Note 1)	61,749	53,824
Net cash provided by operating activities	324,997	264,132
Cash flows from investing activities:
Additions to property and equipment	(15,469)	(34,442)
Additions to capitalized software	(12,271)	(12,533)
Purchases of marketable securities	(81,541)	(60,764)
Prepayments and maturities of marketable securities	64,194	71,782
Sales of marketable securities	0	64
Other investing activities	(11,000)	(1,500)
Net cash used in investing activities	(56,087)	(37,393)
Cash flows from financing activities:
Payment of contingent consideration	(3,965)	(633)
Purchase and retirement of common stock	(197,322)	(219,404)
Proceeds from issuance of common stock	28,867	24,587
Payment of dividends	(105,516)	(103,914)
Net cash used in financing activities	(277,936)	(299,364)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	2,578	(10,545)
Net decrease in cash, cash equivalents and restricted cash	(6,448)	(83,170)
Cash, cash equivalents and restricted cash, beginning of period	787,727	844,547
Cash, cash equivalents and restricted cash, end of period	$ 781,279	$ 761,377