Shareholders' Equity	12 Months Ended
Dec. 31, 2017
Stockholders' Equity Note [Abstract]
Shareholders' Equity	Shareholders' Equity Change in accounting principle As of January 1, 2017, we adopted the updated guidance of "Improvements to Employee Share-Based Compensation Accounting." The adoption of this guidance resulted in an immaterial cumulative effect adjustment to our 2017 beginning retained earnings. For the year ending December 31, 2017, we adopted the updated guidance of "Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income." The adoption of this guidance resulted in a $10.4 million reclassification from accumulated other comprehensive loss to retained earnings during the fourth quarter of 2017. Each of these adoptions are more fully described in Note 3 - "Significant Accounting Policies." 2017 Capital transactions 2% Notes As described in Note 7 - "Debt" in April 2017 holders of approximately $202.5 million of the outstanding principal amount of our 2% Notes exercised their rights to convert their notes into shares of our common stock resulting in the delivery of approximately 29.1 million shares of our common stock to the holders. The transactions included the delivery of approximately 18.7 million from our treasury stock and an additional 10.4 million of newly issued shares. Shareholders' equity was increased by the carrying value of the notes at the time of conversion. 2016 Capital transactions As described in Note 7 - "Debt," in 2016 we issued approximately 18.3 million shares of our common stock as consideration for the purchase of certain of our 2% Notes. As of December 31, 2016, we had repurchased all of the shares issued as partial consideration for our 2% Notes repurchases. The weighted average price paid for the share repurchases was $8.03, which included commissions, and the aggregate purchase amount was $147.1 million. As described in Note 7 - "Debt" the purchase of a portion of our 9% Debentures by MGIC, and corresponding elimination of the purchased 9% Debentures in consolidation, resulted in a reduction to our consolidated shareholders' equity of approximately $6.3 million as of December 31, 2016. This reduction represents the allocated portion of the consideration paid to reacquire the equity component of the 9% Debentures, net of tax. The reduction was recognized in paid-in capital and was less than the amount ascribed to paid-in capital at original issuance of the 9% Debentures. Shareholders Rights Agreement Our Amended and Restated Rights Agreement dated July 23, 2015 seeks to diminish the risk that our ability to use our NOLs to reduce potential future federal income tax obligations may become substantially limited and to deter certain abusive takeover practices. The benefit of the NOLs would be substantially limited, and the timing of the usage of the NOLs could be substantially delayed, if we were to experience an “ownership change” as defined by Section 382 of the Internal Revenue Code. Under the Agreement each outstanding share of our Common Stock is accompanied by one Right. The Distribution Date occurs on the earlier of ten days after a public announcement that a person has become an Acquiring Person, or ten business days after a person announces or begins a tender offer in which consummation of such offer would result in a person becoming an Acquiring Person. An Acquiring Person is any person that becomes, by itself or together with its affiliates and associates, a beneficial owner of 5% or more of the shares of our Common Stock then outstanding, but excludes, among others, certain exempt and grandfathered persons as defined in the Agreement. The Rights are not exercisable until the Distribution Date. Each Right will initially entitle shareholders to buy one-tenth of one share of our Common Stock at a Purchase Price of $45 per full share (equivalent to $4.50 for each one-tenth share), subject to adjustment. Each exercisable Right (subject to certain limitations) will entitle its holder to purchase, at the Rights’ then-current Purchase Price, a number of our shares of Common Stock (or if after the Shares Acquisition Date, we are acquired in a business combination, common shares of the acquiror) having a market value at the time equal to twice the Purchase Price. The Rights will expire on August 1, 2018, or earlier as described in the Agreement. The Rights are redeemable at a price of $0.001 per Right at any time prior to the time a person becomes an Acquiring Person. Other than certain amendments, the Board of Directors may amend the Rights in any respect without the consent of the holders of the Rights.

Shareholders' Equity

Change in accounting principle

As of January 1, 2017, we adopted the updated guidance of "Improvements to Employee Share-Based Compensation Accounting." The adoption of this guidance resulted in an immaterial cumulative effect adjustment to our 2017 beginning retained earnings. For the year ending December 31, 2017, we adopted the updated guidance of "Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income." The adoption of this guidance resulted in a $10.4 million reclassification from accumulated other comprehensive loss to retained earnings during the fourth quarter of 2017. Each of these adoptions are more fully described in Note 3 - "Significant Accounting Policies."

2017 Capital transactions

2% Notes

As described in Note 7 - "Debt" in April 2017 holders of approximately $202.5 million of the outstanding principal amount of our 2% Notes exercised their rights to convert their notes into shares of our common stock resulting in the delivery of approximately 29.1 million shares of our common stock to the holders. The transactions included the delivery of approximately 18.7 million from our treasury stock and an additional 10.4 million of newly issued shares. Shareholders' equity was increased by the carrying value of the notes at the time of conversion.

2016 Capital transactions

As described in Note 7 - "Debt," in 2016 we issued approximately 18.3 million shares of our common stock as consideration for the purchase of certain of our 2% Notes. As of December 31, 2016, we had repurchased all of the shares issued as partial consideration for our 2% Notes repurchases. The weighted average price paid for the share repurchases was $8.03, which included commissions, and the aggregate purchase amount was $147.1 million.

As described in Note 7 - "Debt" the purchase of a portion of our 9% Debentures by MGIC, and corresponding elimination of the purchased 9% Debentures in consolidation, resulted in a reduction to our consolidated shareholders' equity of approximately $6.3 million as of December 31, 2016. This reduction represents the allocated portion of the consideration paid to reacquire the equity component of the 9% Debentures, net of tax. The reduction was recognized in paid-in capital and was less than the amount ascribed to paid-in capital at original issuance of the 9% Debentures.

Shareholders Rights Agreement

Our Amended and Restated Rights Agreement dated July 23, 2015 seeks to diminish the risk that our ability to use our NOLs to reduce potential future federal income tax obligations may become substantially limited and to deter certain abusive takeover practices. The benefit of the NOLs would be substantially limited, and the timing of the usage of the NOLs could be substantially delayed, if we were to experience an “ownership change” as defined by Section 382 of the Internal Revenue Code.

Under the Agreement each outstanding share of our Common Stock is accompanied by one Right. The Distribution Date occurs on the earlier of ten days after a public announcement that a person has become an Acquiring Person, or ten business days after a person announces or begins a tender offer in which consummation of such offer would result in a person becoming an Acquiring Person. An Acquiring Person is any person that becomes, by itself or together with its affiliates and associates, a beneficial owner of 5% or more of the shares of our Common Stock then outstanding, but excludes, among others, certain exempt and grandfathered persons as defined in the Agreement. The Rights are not exercisable until the Distribution Date. Each Right will initially entitle shareholders to buy one-tenth of one share of our Common Stock at a Purchase Price of $45 per full share (equivalent to $4.50 for each one-tenth share), subject to adjustment. Each exercisable Right (subject to certain limitations) will entitle its holder to purchase, at the Rights’ then-current Purchase Price, a number of our shares of Common Stock (or if after the Shares Acquisition Date, we are acquired in a business combination, common shares of the acquiror) having a market value at the time equal to twice the Purchase Price. The Rights will expire on August 1, 2018, or earlier as described in the Agreement. The Rights are redeemable at a price of $0.001 per Right at any time prior to the time a person becomes an Acquiring Person. Other than certain amendments, the Board of Directors may amend the Rights in any respect without the consent of the holders of the Rights.