Capital Requirements	9 Months Ended
Sep. 30, 2016
Statutory Capital [Abstract]
Capital Requirements	Capital Requirements Capital - GSEs Substantially all of our insurance written since 2008 has been for loans purchased by the GSEs. The PMIERs of the GSEs include financial requirements that require a mortgage insurer’s “Available Assets” (generally only the most liquid assets of an insurer) to equal or exceed its “Minimum Required Assets” (which are based on an insurer’s book and are calculated from tables of factors with several risk dimensions and are subject to a floor amount). Based on our interpretation of the PMIERs, as of September 30, 2016, MGIC’s Available Assets are in excess of its Minimum Required Assets; and MGIC is in compliance with the financial requirements of the PMIERs and eligible to insure loans purchased by the GSEs. Statutory Capital Requirements The insurance laws of 16 jurisdictions, including Wisconsin, our domiciliary state, require a mortgage insurer to maintain a minimum amount of statutory capital relative to the risk in force (or a similar measure) in order for the mortgage insurer to continue to write new business. We refer to these requirements as the “State Capital Requirements” and, together with the GSE Financial Requirements, the “Financial Requirements.” While they vary among jurisdictions, the most common State Capital Requirements allow for a maximum risk-to-capital ratio of 25 to 1. A risk-to-capital ratio will increase if (i) the percentage decrease in capital exceeds the percentage decrease in insured risk, or (ii) the percentage increase in capital is less than the percentage increase in insured risk. Wisconsin does not regulate capital by using a risk-to-capital measure but instead requires a minimum policyholder position (“MPP”). The “policyholder position” of a mortgage insurer is its net worth or surplus, contingency reserve and a portion of the reserves for unearned premiums. At September 30, 2016, MGIC’s risk-to-capital ratio was 11.1 to 1, below the maximum allowed by the jurisdictions with State Capital Requirements, and its policyholder position was $1.4 billion above the required MPP of $1.1 billion. In calculating our risk-to-capital ratio and MPP, we are allowed full credit for the risk ceded under our reinsurance transaction with a group of unaffiliated reinsurers. It is possible that under the revised State Capital Requirements discussed below, MGIC will not be allowed full credit for the risk ceded to the reinsurers. If MGIC is not allowed an agreed level of credit under either the State Capital Requirements or the PMIERs, MGIC may terminate the reinsurance agreement, without penalty. At this time, we expect MGIC to continue to comply with the current State Capital Requirements; however, you should read the rest of these financial statement footnotes for information about matters that could negatively affect such compliance. At September 30, 2016, the risk-to-capital ratio of our combined insurance operations (which includes a reinsurance affiliate) was 12.6 to 1. Reinsurance agreements with an affiliate permit MGIC to write insurance with a higher coverage percentage than it could on its own under certain state-specific requirements. A higher risk-to-capital ratio on a combined basis may indicate that, in order for MGIC to continue to utilize reinsurance agreements with its affiliate, additional capital contributions to the reinsurance affiliate could be needed. In each of the first three quarters of 2016 MGIC received approval from the OCI to pay a $16 million dividend to our holding company, which were paid in April, June, and September, respectively, its first dividends since 2008. Any additional dividends paid by MGIC to our holding company in 2016 would require OCI approval under the adjusted statutory net income regulations discussed below. MGIC is subject to statutory regulations as to payment of dividends. The maximum amount of dividends that MGIC may pay in any twelve-month period without regulatory approval by the OCI is the lesser of adjusted statutory net income or 10% of statutory policyholders’ surplus as of the preceding calendar year end. Adjusted statutory net income is defined for this purpose to be the greater of statutory net income, net of realized investment gains, for the calendar year preceding the date of the dividend or statutory net income, net of realized investment gains, for the three calendar years preceding the date of the dividend less dividends paid within the first two of the preceding three calendar years. The OCI recognizes only statutory accounting practices prescribed or permitted by the State of Wisconsin for determining and reporting the financial condition and results of operations of an insurance company. The OCI has adopted certain prescribed accounting practices that differ from those found in other states. Specifically, Wisconsin domiciled companies record changes in the contingency reserves through the income statement as a change in underwriting deduction. As a result, in periods in which MGIC is increasing contingency reserves, statutory net income is lowered. For the year ended December 31, 2015, MGIC’s statutory net income was reduced by $444 million to account for the increase in contingency reserves. The NAIC previously announced that it plans to revise the minimum capital and surplus requirements for mortgage insurers that are provided for in its Mortgage Guaranty Insurance Model Act. In May 2016, a working group of state regulators released an exposure draft of a risk-based capital framework to establish capital requirements for mortgage insurers, although no date has been established by which the NAIC must propose revisions to the capital requirements. We are currently evaluating the impact of the framework contained in the exposure draft, including the potential impact of certain items that have not yet been completely addressed by the framework which include: the treatment of ceded risk, minimum capital floors, and action level triggers. While MGIC currently meets the State Capital Requirements of Wisconsin and all other jurisdictions, it could be prevented from writing new business in the future in all jurisdictions if it fails to meet the State Capital Requirements of Wisconsin, or it could be prevented from writing new business in another jurisdiction if it fails to meet the State Capital Requirements of that jurisdiction, and in each case MGIC does not obtain a waiver of such requirements. It is possible that regulatory action by one or more jurisdictions, including those that do not have specific State Capital Requirements, may prevent MGIC from continuing to write new insurance in such jurisdictions. If we are unable to write business in all jurisdictions, lenders may be unwilling to procure insurance from us anywhere. In addition, a lender’s assessment of the future ability of our insurance operations to meet the State Capital Requirements or the PMIERs may affect its willingness to procure insurance from us. A possible future failure by MGIC to meet the State Capital Requirements or the PMIERs will not necessarily mean that MGIC lacks sufficient resources to pay claims on its insurance liabilities. While we believe MGIC has sufficient claims paying resources to meet its claim obligations on its insurance in force on a timely basis, you should read the rest of these financial statement footnotes for information about matters that could negatively affect MGIC’s claims paying resources.

Capital Requirements

Capital - GSEs

Substantially all of our insurance written since 2008 has been for loans purchased by the GSEs. The PMIERs of the GSEs include financial requirements that require a mortgage insurer’s “Available Assets” (generally only the most liquid assets of an insurer) to equal or exceed its “Minimum Required Assets” (which are based on an insurer’s book and are calculated from tables of factors with several risk dimensions and are subject to a floor amount).

Based on our interpretation of the PMIERs, as of September 30, 2016, MGIC’s Available Assets are in excess of its Minimum Required Assets; and MGIC is in compliance with the financial requirements of the PMIERs and eligible to insure loans purchased by the GSEs.

Statutory Capital Requirements

The insurance laws of 16 jurisdictions, including Wisconsin, our domiciliary state, require a mortgage insurer to maintain a minimum amount of statutory capital relative to the risk in force (or a similar measure) in order for the mortgage insurer to continue to write new business. We refer to these requirements as the “State Capital Requirements” and, together with the GSE Financial Requirements, the “Financial Requirements.” While they vary among jurisdictions, the most common State Capital Requirements allow for a maximum risk-to-capital ratio of 25 to 1. A risk-to-capital ratio will increase if (i) the percentage decrease in capital exceeds the percentage decrease in insured risk, or (ii) the percentage increase in capital is less than the percentage increase in insured risk. Wisconsin does not regulate capital by using a risk-to-capital measure but instead requires a minimum policyholder position (“MPP”). The “policyholder position” of a mortgage insurer is its net worth or surplus, contingency reserve and a portion of the reserves for unearned premiums.

At September 30, 2016, MGIC’s risk-to-capital ratio was 11.1 to 1, below the maximum allowed by the jurisdictions with State Capital Requirements, and its policyholder position was $1.4 billion above the required MPP of $1.1 billion. In calculating our risk-to-capital ratio and MPP, we are allowed full credit for the risk ceded under our reinsurance transaction with a group of unaffiliated reinsurers. It is possible that under the revised State Capital Requirements discussed below, MGIC will not be allowed full credit for the risk ceded to the reinsurers. If MGIC is not allowed an agreed level of credit under either the State Capital Requirements or the PMIERs, MGIC may terminate the reinsurance agreement, without penalty. At this time, we expect MGIC to continue to comply with the current State Capital Requirements; however, you should read the rest of these financial statement footnotes for information about matters that could negatively affect such compliance.

At September 30, 2016, the risk-to-capital ratio of our combined insurance operations (which includes a reinsurance affiliate) was 12.6 to 1. Reinsurance agreements with an affiliate permit MGIC to write insurance with a higher coverage percentage than it could on its own under certain state-specific requirements. A higher risk-to-capital ratio on a combined basis may indicate that, in order for MGIC to continue to utilize reinsurance agreements with its affiliate, additional capital contributions to the reinsurance affiliate could be needed.

In each of the first three quarters of 2016 MGIC received approval from the OCI to pay a $16 million dividend to our holding company, which were paid in April, June, and September, respectively, its first dividends since 2008. Any additional dividends paid by MGIC to our holding company in 2016 would require OCI approval under the adjusted statutory net income regulations discussed below.

MGIC is subject to statutory regulations as to payment of dividends. The maximum amount of dividends that MGIC may pay in any twelve-month period without regulatory approval by the OCI is the lesser of adjusted statutory net income or 10% of statutory policyholders’ surplus as of the preceding calendar year end. Adjusted statutory net income is defined for this purpose to be the greater of statutory net income, net of realized investment gains, for the calendar year preceding the date of the dividend or statutory net income, net of realized investment gains, for the three calendar years preceding the date of the dividend less dividends paid within the first two of the preceding three calendar years. The OCI recognizes only statutory accounting practices prescribed or permitted by the State of Wisconsin for determining and reporting the financial condition and results of operations of an insurance company. The OCI has adopted certain prescribed accounting practices that differ from those found in other states. Specifically, Wisconsin domiciled companies record changes in the contingency reserves through the income statement as a change in underwriting deduction. As a result, in periods in which MGIC is increasing contingency reserves, statutory net income is lowered. For the year ended December 31, 2015, MGIC’s statutory net income was reduced by $444 million to account for the increase in contingency reserves.

The NAIC previously announced that it plans to revise the minimum capital and surplus requirements for mortgage insurers that are provided for in its Mortgage Guaranty Insurance Model Act. In May 2016, a working group of state regulators released an exposure draft of a risk-based capital framework to establish capital requirements for mortgage insurers, although no date has been established by which the NAIC must propose revisions to the capital requirements. We are currently evaluating the impact of the framework contained in the exposure draft, including the potential impact of certain items that have not yet been completely addressed by the framework which include: the treatment of ceded risk, minimum capital floors, and action level triggers.

While MGIC currently meets the State Capital Requirements of Wisconsin and all other jurisdictions, it could be prevented from writing new business in the future in all jurisdictions if it fails to meet the State Capital Requirements of Wisconsin, or it could be prevented from writing new business in another jurisdiction if it fails to meet the State Capital Requirements of that jurisdiction, and in each case MGIC does not obtain a waiver of such requirements. It is possible that regulatory action by one or more jurisdictions, including those that do not have specific State Capital Requirements, may prevent MGIC from continuing to write new insurance in such jurisdictions.

If we are unable to write business in all jurisdictions, lenders may be unwilling to procure insurance from us anywhere. In addition, a lender’s assessment of the future ability of our insurance operations to meet the State Capital Requirements or the PMIERs may affect its willingness to procure insurance from us. A possible future failure by MGIC to meet the State Capital Requirements or the PMIERs will not necessarily mean that MGIC lacks sufficient resources to pay claims on its insurance liabilities. While we believe MGIC has sufficient claims paying resources to meet its claim obligations on its insurance in force on a timely basis, you should read the rest of these financial statement footnotes for information about matters that could negatively affect MGIC’s claims paying resources.