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Defined Contribution and Employee Incentive Plan SIP Grants Table (Detail) (USD $)
In Thousands, except Share data, unless otherwise specified |
71 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
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Mar. 31, 2013
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Dec. 31, 2012
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Jan. 06, 2012
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Dec. 31, 2011
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Dec. 31, 2010
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Dec. 31, 2009
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Dec. 31, 2008
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Dec. 31, 2007
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Jul. 31, 2007
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May 03, 2007
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| SIP Share Grants | ||||||||||
| Shares granted | 3,629,960 | 1,215,866 | 3,411,613 | 2,513,738 | 2,448,031 | 2,065,432 | 1,055,206 | 16,665 | 927,943 | |
| Fair Value - Date of Grant ($000's) | $ 50,500 | $ 18,400 | $ 50,800 | $ 43,200 | $ 42,800 | $ 35,600 | $ 32,900 | $ 400 | $ 27,800 | |
| Shares Granted IPO to Date | 17,284,454 | |||||||||
| Fair Value - Date of Grant ($000's) IPO to Date | $ 302,400 |