CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revenues:
Royalties	$ 374,525	$ 351,641	$ 343,475
License and other	0	10,400	1,500
Total revenues	374,525	362,041	344,975
Operating expenses:
General and administrative	25,469	18,338	41,396
Legal settlement	0	0	92,500
Total operating expenses	25,469	18,338	133,896
Operating income	349,056	343,703	211,079
Non-operating expense, net
Loss on retirement or conversion of convertible notes	0	(766)	(17,648)
Interest and other income, net	7,113	593	468
Interest expense	(29,036)	(36,102)	(43,529)
Total non-operating expense, net	(21,923)	(36,275)	(60,709)
Income before income taxes	327,133	307,428	150,370
Income tax expense	115,464	108,039	58,496
Net income	$ 211,669	$ 199,389	$ 91,874
Net Income per Share [Abstract]
Basic (in Dollars per Share)	$ 1.52	$ 1.43	$ 0.73
Diluted (in Dollars per Share)	$ 1.45	$ 1.15	$ 0.54
Weighted average shares outstanding
Basic (in Shares)	139,711	139,663	126,578
Diluted (in Shares)	146,403	177,441	178,801
Cash dividends declared per common share	$ 0.60	$ 0.60	$ 1.00