Share-Based Compensation (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011
Weighted-average assumptions for options issued during the indicated periods
Dividend yield	0.00%	0.00%	0.00%	0.00%
Expected volatility	58.60%	68.40%	58.80%	63.00%
Risk-free interest rate	0.50%	0.60%	1.90%	2.10%
Expected life of options (in years)	2.0	2.0	3.8	4.3
Weighted-average grant-date fair value	$ 12.24	$ 11.12	$ 19.17	$ 12.60
Stock option activity in shares and weighted average price
Options outstanding, beginning of period			$ 29.67
Options outstanding, beginning of period, shares			1,361,779
Options granted			$ 42.56
Options granted, shares			307,394
Options canceled			$ 55.19
Options canceled, shares			(67,529)
Options exercised			$ 22.71
Options exercised, shares			(218,313)
Options outstanding, end of period	$ 32.39		$ 32.39
Options outstanding, end of period, shares	1,383,331	1,500,000	1,383,331	1,500,000
Options exercisable, end of period					$ 30.87
Options exercisable, end of period, shares	736,950		736,950
Restricted stock activity
Restricted shares outstanding, beginning of period			$ 22.87
Restricted shares outstanding, beginning of period, shares			734,286
Restricted shares granted			$ 42.29
Restricted shares granted, shares			416,800
Restricted shares canceled			$ 30.85
Restricted shares canceled, shares			(26,558)
Restricted shares vested			$ 24.69
Restricted shares vested, shares			(334,046)
Restricted shares outstanding, end of period	$ 32.13		$ 32.13
Restricted shares outstanding, end of period, shares	790,482		790,482