Long-term Incentive Plans (Details Textuals) (USD $)
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3 Months Ended | 6 Months Ended | 6 Months Ended | 3 Months Ended | 6 Months Ended | ||||||
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Jun. 30, 2011
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Jun. 30, 2010
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Jun. 30, 2011
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Jun. 30, 2010
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May 18, 2011
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Jun. 30, 2011
Restricted Stock [Member]
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Jun. 30, 2011
Restricted Stock Units [Member]
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Jun. 30, 2010
Restricted Stock Units [Member]
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Jun. 30, 2011
Restricted Stock Units [Member]
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Jun. 30, 2010
Restricted Stock Units [Member]
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Dec. 31, 2010
Restricted Stock Units [Member]
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Unrecognized compensation cost, related to unvested restricted stock, total | $ 29,000,000 | ||||||||||
Expected weighted average period to recognize compensation cost on restricted stock (in years) | 2.0 | ||||||||||
Vesting period for Restricted Stock Units | 3 years | ||||||||||
Compensation expense related to Restricted Stock Units | 200,000 | 200,000 | 500,000 | 200,000 | |||||||
Liabilities under Restricted Stock Units | 600,000 | 600,000 | 200,000 | ||||||||
Long Term Incentive Plans (Textuals) [Abstract] | |||||||||||
Common Stock available for awards pursuant to the 2011 plan | 11,750,000 | 11,750,000 | |||||||||
Number of additional shares of common stock available pursuant to the terms of the 2007 Plan | 178,815 | ||||||||||
Minimum vested period, restricted stock | 3 years | 3 years | 3 years | 3 years | |||||||
Maximum vested period, restricted stock | 4 years | 4 years | 4 years | 4 years | |||||||
Grant of restricted stocks under the Plans | 67,198 | 53,919 | 900,000 | 1,100,000 | |||||||
Weighted average grant price | $ 19.90 | $ 20.86 | $ 22.16 | $ 19.20 | |||||||
Restricted stock, vested | 55,128 | 53,539 | 900,000 | 700,000 | |||||||
Fair value of additional restricted stock, vested | $ 1,100,000 | $ 1,100,000 | $ 20,000,000 | $ 13,000,000 |