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Represents the total fair value of nonvested equity stock units granted during the period.

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Represents the total fair value of options for granted during the period.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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The period of time an equity-based award is expected to be outstanding. An equity-based award's expected term is generally determined based on, among other factors, the instrument's contractual term and the effects of employees' expected exercise and post-vesting employment termination behavior.

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The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Net number of share options (or share units) granted during the period.

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Number of shares issued during the period as a result of an employee stock purchase plan.

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-Name Regulation S-X (SX)

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Equity Incentive Plans and Stock-Based Compensation (Details 3) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Valuation assumptions
Dividend yield (as a percent)	0.00%	0.00%	0.00%	0.00%	0.00%
Stock Option Plans
Stock-Based Compensation
Stock option granted (in shares)	487,550	93,300	2,199,761	1,818,623
Estimated total grant date fair value	$ 4.6	$ 1.0	$ 22.9	$ 23.9
Stock-based compensation	5.0	5.6	15.2	17.3
Unrecognized compensation cost net of expected forfeitures	39.3		39.3
Expected weighted-average period for recognition of compensation cost (in years)			3.4
Total fair value of shares vested	142.0		142.0
Total intrinsic value of options exercised	1.7	1.9	5.7	7.1
Net proceeds from employee stock option			6.4
Valuation assumptions
Dividend yield (as a percent)	0.00%	0.00%	0.00%	0.00%	0.00%
Expected stock price volatility (as a percent)	75.00%	60.00%
Expected stock price volatility rate minimum (as a percent)			50.00%	60.00%
Expected stock price volatility rate maximum (as a percent)			75.00%	69.00%
Risk free interest rate (as a percent)	2.30%	2.30%
Risk free interest rate minimum (as a percent)			2.30%	2.30%
Risk free interest rate maximum (as a percent)			2.80%	3.20%
Expected term (in years)	6.1	6.1
Expected term, minimum (in years)			6.0	5.9
Expected term, maximum (in years)			6.1	6.1
Weighted-average fair value of stock options granted (in dollars per share)	$ 9.48	$ 10.88	$ 10.43	$ 13.15
Employee Stock Purchase Plans
Stock-Based Compensation
Shares issued under employee stock purchase plans (in shares)			146,034	161,293
Price per share of shares issued (in dollars per share)			$ 16.50	$ 13.56
Shares available for issuance (in shares)	439,734		439,734
Shares issued at discount from the fair market value (as a percent)			15.00%
Stock-based compensation	0.5	0.4	1.3	1.3
Unrecognized compensation cost net of expected forfeitures	0.1		0.1
Expected weighted-average period for recognition of compensation cost (in years)			0.083
Valuation assumptions
Dividend yield (as a percent)			0.00%	0.00%	0.00%
Expected stock price volatility (as a percent)			56.00%	54.00%
Risk free interest rate (as a percent)			0.10%	0.30%
Expected term (in years)			0.5	0.5
Weighted-average fair value of purchase rights granted under the purchase plan (in dollars per share)			$ 5.96	$ 7.46
Weighted-Average Grant-Date Fair Value
Granted (in dollars per share)			$ 5.96	$ 7.46
Shares including nonvested equity stock and stock units
Stock-Based Compensation
Stock-based compensation	1.8	1.5	5.1	4.6
Unrecognized compensation cost net of expected forfeitures	9.0		9.0
Expected weighted-average period for recognition of compensation cost (in years)			2.0
Valuation assumptions
Weighted-average fair value of purchase rights granted under the purchase plan (in dollars per share)			$ 18.99
General nonvested equity stock service period (in years)			4
Nonvested equity stock service period for directors (in years)			1
Non vested equity stock granted fair value	$ 1.1		$ 5.6
Nonvested equity stock and stock units
Nonvested at the beginning of the period (in shares)			718,007
Granted (in shares)	80,000		293,554
Vested (in shares)			(245,697)
Forfeited (in shares)			(14,934)
Nonvested at the end of the period (in shares)	750,930		750,930
Weighted-Average Grant-Date Fair Value
Nonvested at the beginning of the period (in dollars per share)			$ 18.23
Granted (in dollars per share)			$ 18.99
Vested (in dollars per share)			$ 17.59
Forfeited (in dollars per share)	$ 21.76		$ 21.76
Nonvested at the end of the period (in dollars per share)	$ 18.67		$ 18.67