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Equity (Details) (USD $) In Millions, except Share data, unless otherwise specified | 3 Months Ended | 9 Months Ended |  | 0 Months Ended
--- | --- | --- | --- | ---
Sep. 30, 2014 | Jun. 30, 2014 | Mar. 31, 2014 | Sep. 30, 2013 | Sep. 30, 2014 | Sep. 30, 2013 | Aug. 29, 2014 | Oct. 17, 2014 Subsequent Event [Member]
Class of Stock [Line Items] |  |  |  |  |  |  |  |
Common stock issued under stock compensation plan (in shares) |  |  |  |  | 1,164,518 |  |  |
Stock repurchased (in shares) |  |  |  |  | 351,565 |  |  |
Net increase in period (in shares) |  |  |  |  | 812,953 |  |  |
Increase in its quarterly cash dividend rate |  | $ 0.02 |  |  |  |  |  |
Dividends declared (in dollars per share) | $ 0.16 | $ 0.16 | $ 0.14 | $ 0.14 | $ 0.46 | $ 0.42 |  |
Dividends payable |  |  |  |  |  |  | $ 23.4 |
Dividends paid |  |  |  |  |  |  |  | $ 23.4

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