Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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The number of shares issued in exchange for the original debt being converted in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or payments in the period.

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The price per share of the conversion feature embedded in the debt instrument.

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Face (par) amount of debt instrument at time of issuance.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Gross amount of debt extinguished.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of contingently issuable shares. Contingently issuable shares are those shares that are issuable for little or no cash contingent on certain conditions being met.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of convertible debt securities using the if-converted method.

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The cash outflow to repay long-term debt that is not secured by collateral. Excludes repayments of tax exempt unsecured debt.

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This element represents the weighted average total number of shares issued throughout the period including the first (beginning balance outstanding) and last (ending balance outstanding) day of the period before considering any reductions (for instance, shares held in treasury) to arrive at the weighted average number of shares outstanding. Weighted average relates to the portion of time within a reporting period that common shares have been issued and outstanding to the total time in that period. Such concept is used in determining the weighted average number of shares outstanding for purposes of calculating earnings per share (basic).

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Earnings Per Share (Narrative) (Details) (USD $)	3 Months Ended		6 Months Ended
Earnings Per Share (Narrative) (Details) (USD $)	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Earnings Per Share [Line Items]
Debt instrument, convertible, settlement in cash			$ 105,325,000	$ 150,000,000
Anti-dilutive common stock equivalents, shares	304,600	123,077	182,218	61,878
4.0% Notes [Member]
Earnings Per Share [Line Items]
Debt instrument, convertible, common shares issued			4,200,000
2011 4.0% Notes [Member]
Earnings Per Share [Line Items]
Debt instrument, convertible, settlement in cash			105,300,000
Debt instrument, convertible, common shares issued			3,600,000
Weighted average shares issued	600,000		300,000
2009 4.0% Notes [Member]
Earnings Per Share [Line Items]
Debt instrument, convertible, common shares issued			600,000
Unsecured Debt [Member] \| 4.0% Notes [Member]
Earnings Per Share [Line Items]
Debt instrument, convertible, interest rate	4.00%		4.00%
Debt instrument, convertible, maturity and conversion			115,000,000
Debt instrument, convertible, conversion price per share	$ 15.76		$ 15.76
Unsecured Debt [Member] \| 2011 4.0% Notes [Member]
Earnings Per Share [Line Items]
Debt instrument, convertible, interest rate	4.00%		4.00%
Debt instrument, convertible, maturity and conversion			105,300,000
Debt instrument, convertible, conversion price per share	$ 15.76		$ 15.76
Unsecured Debt [Member] \| 2009 4.0% Notes [Member]
Earnings Per Share [Line Items]
Debt instrument, convertible, interest rate	4.00%		4.00%
Debt instrument, convertible, maturity and conversion			9,600,000
Debt instrument, convertible, conversion price per share	$ 15.76		$ 15.76
Convertible Debt [Member] \| 2011 4.25% Notes [Member]
Earnings Per Share [Line Items]
Weighted average equivalent premium shares	3,693,000	3,048,000	3,703,000	2,971,000
Convertible Debt [Member] \| 2011 4.0% Notes [Member]
Earnings Per Share [Line Items]
Weighted average equivalent premium shares	3,300,000	3,187,000	3,600,000	3,104,000
Convertible Debt [Member] \| 2009 4.0% Notes [Member]
Earnings Per Share [Line Items]
Dilutive shares, 2009 4.0% Notes	600,000		600,000
Convertible Debt [Member] \| Unsecured Debt [Member] \| 4.25% Convertible Notes [Member]
Earnings Per Share [Line Items]
Principal amount	100,000,000		100,000,000
Debt instrument, convertible, interest rate	4.25%		4.25%
Debt instrument, convertible, conversion price per share	$ 15.48		$ 15.48
Convertible Debt [Member] \| Unsecured Debt [Member] \| 2011 4.25% Notes [Member]
Earnings Per Share [Line Items]
Principal amount	97,000,000		97,000,000
Debt instrument, convertible, interest rate	4.25%		4.25%
Debt instrument, convertible, conversion price per share	$ 15.48		$ 15.48
Convertible Debt [Member] \| Unsecured Debt [Member] \| 2009 4.25% Notes [Member]
Earnings Per Share [Line Items]
Principal amount	$ 3,000,000		$ 3,000,000
Debt instrument, convertible, interest rate	4.25%		4.25%
Debt instrument, convertible, conversion price per share	$ 15.48		$ 15.48