Borrowing Arrangements	9 Months Ended
Sep. 30, 2017
Debt Disclosure [Abstract]
Borrowing Arrangements	Note 6. Borrowing Arrangements Bank line of credit As of September 30, 2017, we have access to a $100 million bank revolving line of credit with a $25 million letter of credit sublimit that expires on November 3, 2020. As of September 30, 2017, a total of $99.1 million remains available under the facility due to $0.9 million outstanding letters of credit, which reduce the availability for letters of credit to $24.1 million. We had no borrowings outstanding on our line of credit as of September 30, 2017. Bonds with a fair value of $109.5 million were pledged as collateral on the line at September 30, 2017. The securities pledged as collateral have no trading restrictions and are reported as available-for-sale securities in the Statements of Financial Position as of September 30, 2017. The bank requires compliance with certain covenants, which include leverage ratios and debt restrictions, for our line of credit. We are in compliance with all bank covenants at September 30, 2017. Term loan credit facility On November 7, 2016, we entered into a credit agreement for a $100 million senior secured draw term loan credit facility ("Credit Facility") for the acquisition of real property and construction of an office building that will serve as part of our principal headquarters. Under the agreement, $25 million will be drawn on December 1, 2016, June 1, 2017, December 1, 2017, and June 1, 2018 ("Draw Period"). During the Draw Period, we will make monthly interest only payments under the Credit Facility and thereafter the Credit Facility converts to a fully-amortized term loan with monthly payments of principal and interest over a period of 28 years. Borrowings under the Credit Facility will bear interest at a fixed rate of 4.35%. In addition, we are required to pay a quarterly commitment fee of 0.08% on the unused portion of the Credit Facility during the Draw Period. Total draws against the facility are $50 million as of September 30, 2017. Bonds with a fair value of $109.7 million were pledged as collateral for the facility and are reported as available-for-sale securities in the Statements of Financial Position as of September 30, 2017. The bank requires compliance with certain covenants, which include leverage ratios, debt restrictions and minimum net worth, for our Credit Facility. We are in compliance with all covenants at September 30, 2017. Amounts drawn from the Credit Facility are reported at carrying value on our Statements of Financial Position, net of unamortized loan origination and commitment fees. The estimated fair value of this borrowing at September 30, 2017 was $47.9 million. The estimated fair value was determined using estimates based upon interest rates and credit spreads and are classified as Level 3 in the fair value hierarchy as of September 30, 2017. The scheduled maturity of the $100 million Credit Facility begins on January 1, 2019 with annual principal payments of $1.9 million in 2019, $2.0 million in 2020, $2.0 million in 2021, $2.1 million in 2022 and $92.0 million thereafter.

Note 6. Borrowing Arrangements

Bank line of credit

As of September 30, 2017, we have access to a $100 million bank revolving line of credit with a $25 million letter of credit sublimit that expires on November 3, 2020. As of September 30, 2017, a total of $99.1 million remains available under the facility due to $0.9 million outstanding letters of credit, which reduce the availability for letters of credit to $24.1 million. We had no borrowings outstanding on our line of credit as of September 30, 2017. Bonds with a fair value of $109.5 million were pledged as collateral on the line at September 30, 2017. The securities pledged as collateral have no trading restrictions and are reported as available-for-sale securities in the Statements of Financial Position as of September 30, 2017. The bank requires compliance with certain covenants, which include leverage ratios and debt restrictions, for our line of credit. We are in compliance with all bank covenants at September 30, 2017.

Term loan credit facility

On November 7, 2016, we entered into a credit agreement for a $100 million senior secured draw term loan credit facility ("Credit Facility") for the acquisition of real property and construction of an office building that will serve as part of our principal headquarters. Under the agreement, $25 million will be drawn on December 1, 2016, June 1, 2017, December 1, 2017, and June 1, 2018 ("Draw Period"). During the Draw Period, we will make monthly interest only payments under the Credit Facility and thereafter the Credit Facility converts to a fully-amortized term loan with monthly payments of principal and interest over a period of 28 years. Borrowings under the Credit Facility will bear interest at a fixed rate of 4.35%. In addition, we are required to pay a quarterly commitment fee of 0.08% on the unused portion of the Credit Facility during the Draw Period. Total draws against the facility are $50 million as of September 30, 2017. Bonds with a fair value of $109.7 million were pledged as collateral for the facility and are reported as available-for-sale securities in the Statements of Financial Position as of September 30, 2017. The bank requires compliance with certain covenants, which include leverage ratios, debt restrictions and minimum net worth, for our Credit Facility. We are in compliance with all covenants at September 30, 2017.

Amounts drawn from the Credit Facility are reported at carrying value on our Statements of Financial Position, net of unamortized loan origination and commitment fees. The estimated fair value of this borrowing at September 30, 2017 was $47.9 million. The estimated fair value was determined using estimates based upon interest rates and credit spreads and are classified as Level 3 in the fair value hierarchy as of September 30, 2017.

The scheduled maturity of the $100 million Credit Facility begins on January 1, 2019 with annual principal payments of $1.9 million in 2019, $2.0 million in 2020, $2.0 million in 2021, $2.1 million in 2022 and $92.0 million thereafter.