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Financing Arrangements (Details 2) (USD $)
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3 Months Ended | 9 Months Ended | 3 Months Ended | 9 Months Ended | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
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Sep. 30, 2013
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Dec. 31, 2012
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Sep. 30, 2013
Other borrowings
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Sep. 30, 2013
1.5% Convertible Senior Notes due February 15, 2024
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Sep. 30, 2012
1.5% Convertible Senior Notes due February 15, 2024
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Sep. 30, 2013
1.5% Convertible Senior Notes due February 15, 2024
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Sep. 30, 2012
1.5% Convertible Senior Notes due February 15, 2024
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Dec. 31, 2012
1.5% Convertible Senior Notes due February 15, 2024
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Feb. 29, 2004
1.5% Convertible Senior Notes due February 15, 2024
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Mar. 31, 2013
5.625% Municipal Bonds
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Sep. 30, 2013
5.625% Municipal Bonds
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Dec. 31, 2012
5.625% Municipal Bonds
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| Financing Arrangements | ||||||||||||
| Carrying value of the equity component | $ 19,519,000 | $ 19,519,000 | $ 19,519,000 | |||||||||
| Principal amount and carrying value of the liability component | 18,398,000 | 18,398,000 | 18,472,000 | |||||||||
| Common stock, par value (in dollars per share) | $ 0.01 | $ 0.01 | ||||||||||
| Conversion rate per $1,000 principal amount of Notes (in shares) | 36.6729 | |||||||||||
| Debt instrument, coupon interest | 100,000 | 100,000 | 200,000 | 200,000 | ||||||||
| Debt instrument, convertible, if-converted value | 48,000,000 | |||||||||||
| Debt instrument interest rate (as a percent) | 1.50% | 1.50% | 1.50% | 1.50% | 5.625% | |||||||
| Redemption price as a percentage of the principal amount (as a percent) | 100.00% | 100.00% | ||||||||||
| Borrowings under short-term credit facility | $ 7,000,000 | |||||||||||