Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2011
Assets
Cash and cash equivalents	$ 178,476	$ 228,993	$ 187,922
Short-term investments	114,806	148,488	152,612
Restricted cash	1,123	2,128	1,820
Accounts receivable, net	54,411	48,106	59,798
Deferred income taxes	12,566	9,759	5,402
Prepaid expenses and other current assets	17,832	18,814	24,388
Total current assets	379,214	456,288	431,942
Property and equipment, net	198,493	201,257	196,579
Deferred income taxes	34,081	33,267	28,125
Other assets	49,516	38,006	44,869
Total assets	661,304	728,818	701,515
Liabilities and Shareholders' Equity
Accounts payable	77,664	78,876	72,689
Accrued compensation and benefits	13,323	21,438	19,345
Other current liabilities	50,920	18,190	61,321
Deferred revenue	180,147	226,543	265,540
Total current liabilities	322,054	345,047	418,895
Long-term debt	175,000	150,000	150,000
Other liabilities	72,629	64,972	52,151
Total liabilities	569,683	560,019	621,046
Shareholders' equity:
Preferred stock, $.01 par value, 5,000,000 shares authorized, none issued	0	0	0
Common stock, $.01 par value, 300,000,000 shares authorized, 37,068,904 issued	371	371	371
Capital surplus	194,027	189,573	177,594
Retained earnings	884,230	827,675	607,765
Accumulated other comprehensive (loss)	(9,316)	(9,479)	(4,563)
Treasury stock, 12,934,377, 10,969,425 and 8,999,196 shares, at cost	(977,691)	(839,341)	(700,698)
Total shareholders' equity	91,621	168,799	80,469
Total liabilities and shareholders' equity	$ 661,304	$ 728,818	$ 701,515