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Equity (Details 2) (USD $)
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6 Months Ended | 1 Months Ended | 3 Months Ended | 6 Months Ended | |
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Jun. 30, 2012
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Jun. 30, 2011
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Nov. 30, 2010
CEP II
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Jun. 30, 2012
CEP II
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Jun. 30, 2012
CEP II
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| Equity | |||||
| Common stock shares issued | 1,119,892 | 1,119,892 | |||
| Common stock shares issued in connection with stock options exercised | 318,175 | ||||
| Common stock shares issued through dividend reinvestment plan | 1,336 | 1,809 | |||
| Common stock shares issued in connection with stock grants | 95,941 | 498,810 | |||
| Number of shares of stock grants withheld | 120,078 | 126,928 | |||
| Restricted common stock shares forfeited | 4,027 | ||||
| Options of common stock granted to employees (in shares) | 113,804 | ||||
| Maximum value of shares of common stock that can be sold (in dollars) | $ 500,000,000 | ||||
| Period during which common stock can be sold | 36 months | ||||
| Shares sold, average sales price (in dollars per share) | $ 140.14 | $ 140.14 | |||
| Net proceeds from sales of shares (in dollars) | $ 175,682,000 | $ 264,134,000 | $ 154,588,000 | $ 154,588,000 | |
| X | ||||||||||
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- Definition
The maximum value of common stock which the entity is authorized to issue under the program. No definition available.
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- Definition
Represents the period during which common stock can be sold under the program. No definition available.
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- Details
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- Definition
Amount per share assigned to the consideration received for shares issued. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The cash inflow from the additional capital contribution to the entity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Net number of share options (or share units) granted during the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
For net-share settlement of share-based awards when the employer settles employees' income tax withholding obligations, this element represents the number of shares the employees use to repay the employer. No definition available.
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- Definition
Number of shares issued during the period from a dividend reinvestment plan (DRIP). A dividend reinvestment plan allows the shareholders to reinvest dividends paid to them by the entity on new issues of stock by the entity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Number of new stock issued during the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Number of shares related to Restricted Stock Award forfeited during the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Gross number of shares (or other type of equity) issued during the period as a result of any equity-based compensation plan other than an employee stock ownership plan (ESOP). Shares issued could result from the issuance of restricted stock, the exercise of stock options, stock issued under employee stock purchase plans, and/or other employee benefit plans. No definition available.
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| X | ||||||||||
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- Definition
Number of share options (or share units) exercised during the current period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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