Subsequent Events (Notes)	3 Months Ended
Subsequent Events (Notes)	Mar. 31, 2020
Subsequent Events [Abstract]
Subsequent Events [Text Block]	Subsequent Events Governmental (international, federal, state, and local) directives to contain or delay the spread of the COVID-19 pandemic have resulted in directives requiring social distancing, operational alteration or temporary closure of most non-essential businesses to public access, and “sheltering-in-place” of everyone other than essential service workers. These actions have disrupted regular commerce, supply chains, and travel. Most of these governmental directives were issued in First Quarter 2020, and to date, these directives have significantly limited the operations of those businesses that are considered non-essential, and their employees, along with the general public who are "sheltering-in-place." As a result, we are expecting that claims frequency for our personal and commercial automobile lines of business will decline because of the reduced miles being driven consistent with the governmental directives. As the number of vehicles we insure has not significantly declined and we expect that frequencies will return to normal after the governmental directives expire or are lifted, we do not believe that changes in our filed rating plans are appropriate. Unlike our workers compensation and general liability lines of business policies, in which we anticipate a decline in sales and payroll exposures, our commercial and personal automobile policies do not provide for an audit that would reduce annual premium. Because of the unprecedented nature of the COVID-19-related governmental directives and the associated expected short-term favorable claims frequency impact, we felt it was appropriate to seek regulatory approval during April to provide a premium-based credit to our personal and commercial automobile customers. The premium-based credit would provide for an amount to be returned to customers with in-force policies equivalent to 15% of their April and May premiums. This approval process has been completed and this premium-based credit will be recorded as other insurance expense in the second quarter of 2020 of approximately $20 million. We believe the impact to our other insurance expenses will be largely offset by a reduction in our loss and loss expenses as a result of expected reduced insured automobile accident claims frequency in those respective months. The COVID-19-related governmental directives also have induced significant uncertainty and volatility in the financial markets and decreased equity market valuations. To date, this has been reflected in the market values of our invested assets and the corresponding OTTI charges discussed in Note 4. "Investments." However, as our other investment portfolio largely consists of alternative investments that are recorded on a one quarter lag, the impact of the First Quarter 2020 financial market volatility on those alternative investments will not be reflected in our Financial Statements until second quarter of 2020. While it is extremely difficult to accurately estimate the potential losses associated with this portion of our investment portfolio, we performed a sensitivity analysis that indicates a potential pre-tax loss of between $15 million and $20 million. However, while these are our current estimates, our second quarter net investment income will reflect the actual decrease reported by these alternative investments as of March 31, 2020. We cannot predict the extent and duration of the current COVID-19-related governmental directives, which also may change based on future COVID-19 infection rates, nor can we predict COVID-19-related impacts on the economy or financial markets or changes in legislation. A change in any of these factors, however, could impact our estimates and assumptions in future periods. Changes in these assumptions and estimates in future periods may be material to the results of our operations and could materially reduce our net income, cash flow, and stockholders' equity. We also expect to incur estimated pre-tax net losses of approximately $35 million due to several severe storms in April, which impacted parts of the mid-west and east coast regions of the United States with damaging wind and tornadoes.