Represents the common stock units to be issued as a percentage of cash compensation deferred.

No definition available.

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Represents the minimum cash compensation required in order to qualify for elective participation in the plan.

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Represents the percentage of deferred compensation that is fully vested at all times and non-forfeitable.

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The percentage of the deferred compensation representing the match that is contingent only on employment with the Company.

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The fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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Reductions in the entity's income taxes that arise when compensation cost (from other than stock options awards) recognized on the entity's tax return exceeds compensation cost from other than stock option awards recognized on the income statement. This element increases net cash provided by operating activities.

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As of the balance sheet date, the aggregate unrecognized cost of equity-based awards made to employees under equity-based compensation awards that have yet to vest.

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The weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, using a decimal to express in number of years.

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This element represents nonvested share-based payment awards that contain non-forfeitable rights to dividends or dividend equivalents (whether paid or unpaid). Basic and dilutive earnings per share are generally disclosed for such shares using the two-class method.

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Description of the period of time over which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, which may be expressed in a variety of ways (for example, in years, month and year).

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

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The weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect during the reporting period as a result of the occurrence of a terminating event specified in the contractual agreement of the plan.

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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 weighted average fair value at grant date for nonvested equity-based awards issued 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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The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

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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 weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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Employee and Non Employee Director Stock and Benefit Plans (Details 5) (USD $)	12 Months Ended					12 Months Ended				12 Months Ended						1 Months Ended
	Dec. 31, 2011 Restricted share awards Y	Dec. 31, 2010 Restricted share awards	Dec. 31, 2009 Restricted share awards	Dec. 31, 2011 Performance-based share awards	Dec. 31, 2011 Market-based share awards	Dec. 31, 2011 Phantom share awards Y	Dec. 31, 2010 Phantom share awards	Dec. 31, 2009 Phantom share awards	Dec. 31, 2011 Market-based units	Dec. 31, 2011 2007 Plan Phantom share awards	Dec. 31, 2010 2007 Plan Phantom share awards	Dec. 31, 2009 2007 Plan Phantom share awards	Dec. 31, 2011 Stock Unit Award Program (SUA)	Dec. 31, 2010 Stock Unit Award Program (SUA)	Dec. 31, 2009 Stock Unit Award Program (SUA)	Jun. 30, 2003 Stock Unit Award Program (SUA) First amendment	Jan. 31, 2006 Stock Unit Award Program (SUA) Second amendment
Number of Shares
Outstanding at the beginning of the period (in shares)	2,935,323	1,224,457	465,527	316,803	475,255	259,370	91,013		40,684				364,167	677,379	860,168
Granted (in shares)	1,343,172	2,193,239	999,554			205,760	212,047	92,387							6,743
Vested (in shares)	(843,053)	(317,489)	(178,783)			(67,383)	(25,285)						(288,917)	(311,106)	(168,248)
Forfeited (in shares)	(380,138)	(164,884)	(61,841)				(18,405)	(1,374)					(3,670)	(2,106)	(21,284)
Outstanding at the end of the period (in shares)	3,055,304	2,935,323	1,224,457	316,803	475,255	397,747	259,370	91,013	40,684				71,580	364,167	677,379
Non-forfeitable (in shares)													66,280
Weighted Average Grant Date Fair Value
Outstanding at the beginning of the period (in dollars per share)	$ 19.44	$ 27.03	$ 44.64			$ 18.51	$ 23.45						$ 29.82	$ 29.32	$ 30.56
Granted (in dollars per share)	$ 16.65	$ 16.26	$ 22.47			$ 18.67	$ 16.96	$ 23.45							$ 22.65
Vested (in dollars per share)	$ 23.29	$ 25.91	$ 43.66			$ 19.21	$ 23.45						$ 28.98	$ 28.67	$ 35.61
Forfeited (in dollars per share)	$ 16.71	$ 21.02	$ 37.78				$ 18.25	$ 23.45					$ 15.40	$ 32.54	$ 27.71
Outstanding at the end of the period (in dollars per share)	$ 17.49	$ 19.44	$ 27.03			$ 18.47	$ 18.51	$ 23.45					$ 33.95	$ 29.82	$ 29.32
Additional disclosures
Unrecognized compensation costs	$ 21,700,000					$ 2,400,000
Weighted average period over which unrecognized compensation costs are expected to be recognized (in years)	1.29					1.07
Grant date fair value	19,600,000
Tax shortfalls related to the vesting	2,200,000	1,100,000	1,700,000
Vesting period (in years)										3 years
Share-based compensation expense	20,600,000	15,400,000	14,600,000							1,100,000	1,100,000	600,000	(200,000)	500,000	1,300,000
Tax benefit related to share-based compensation expense	8,400,000	6,200,000	5,800,000							300,000	400,000	200,000	(100,000)	200,000	500,000
Common stock units to be issued as a percentage of cash compensation deferred													115.00%			130.00%	120.00%
Percentage of the deferred compensation representing the match that is contingent only on employment with the Company																30.00%	20.00%
Minimum cash compensation required to qualify for elective participation under the plan																	200,000
Earnings of employees for which participation is mandatory																$ 200,000
Percentage of deferred compensation representing the match that vests on third anniversary																50.00%	100.00%
Percentage of deferred compensation representing the match that vests on sixth anniversary																50.00%
Percentage of deferred compensation that is fully vested at all times and non-forfeitable																100.00%	100.00%