Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Cash flows from operating activities:
Net income	$ 99,974	$ 112,153
Adjustments to reconcile net income to net cash provided by operating activities	(24,861)	(19,313)
Net cash provided by operating activities	75,113	92,840
Cash flows from investing activities:
Additions to property and equipment	(16,344)	(6,973)
Additions to capitalized software	(18,214)	(20,537)
Purchases of marketable securities	(13,827)	(36,596)
Prepayments and maturities of marketable securities	22,170	23,134
Sales of marketable securities	737	37,408
Purchases of other investments	(2,720)	0
Sales of other investments	0	4,905
Net cash (used in) provided by investing activities	(28,198)	1,341
Cash flows from financing activities:
Payments on long-term debt	0	(55,000)
Purchase and retirement of common stock	(80,899)	(94,137)
Proceeds from issuance of common stock	14,765	20,845
Tax benefit on stock options exercised	(1,638)	2,171
Payment of dividends	(52,635)	(22,041)
Net cash used in financing activities	(120,407)	(148,162)
Net decrease in cash and cash equivalents	(73,492)	(53,981)
Cash and cash equivalents, beginning of period	420,986	496,292
Cash and cash equivalents, end of period	$ 347,494	$ 442,311