6) Debt Commitments

Credit Facility, Notes Payable, Industrial Revenue Bonds, and Commitments

Debt obligations and letters of credit outstanding at the end of each period consisted of the following:



	March 31, 2019			December 31, 2018
Outstanding loans under unsecured revolving credit facility	$	335.0		365.0
2.00% Senior unsecured promissory note payable	40.0			40.0
2.45% Senior unsecured promissory note payable	35.0			35.0
3.22% Senior unsecured promissory note payable	60.0			60.0
Industrial revenue bonds	19.0			—
Total debt	489.0			500.0
Less: Current portion of debt	(4.4		)	(3.0	)
Long-term debt	$	484.6		497.0

Outstanding letters of credit under unsecured revolving credit facility - contingent obligation	$	36.3		36.3

Unsecured Revolving Credit Facility

We have a $700.0 committed unsecured revolving credit facility ('Credit Facility'). The Credit Facility includes a committed letter of credit subfacility of $55.0. The commitments under the Credit Facility will expire (and any borrowings outstanding under the Credit Facility will become due and payable) on November 30, 2023. In the next twelve months, we have the ability and intent to repay a portion of the outstanding loans using cash; therefore, we have classified this portion as a current liability. The Credit Facility contains certain financial and other covenants, and our right to borrow under the Credit Facility is conditioned upon, among other things, our compliance with these covenants. We are currently in compliance with these covenants.

Borrowings under the Credit Facility generally bear interest at a rate per annum equal to the London Interbank Offered Rate ('LIBOR') for interest periods of various lengths selected by us, plus 0.95%. Based on the interest periods we have chosen, our weighted per annum interest rate at March 31, 2019 was approximately 3.4%. We pay a commitment fee for the unused portion of the Credit Facility. This fee is either 0.10% or 0.125% per annum based on our usage of the Credit Facility.

Senior Unsecured Promissory Notes Payable

We have issued senior unsecured promissory notes under our master note agreement (the 'Master Note Agreement') in the aggregate principal amount of $135.0. Our aggregate borrowing capacity under the Master Note Agreement is $600.0; however, none of the institutional investors party to that agreement are committed to purchase notes thereunder.

The notes currently issued under our Master Note Agreement consist of three series. The first is in an aggregate principal amount of $40.0, bears interest at a fixed rate of 2.00% per annum, and is due and payable on July 20, 2021. The second is in an aggregate principal amount of $35.0, bears interest at a fixed rate of 2.45% per annum, and is due and payable on July 20, 2022. The third is in an aggregate principal amount of $60.0, bears interest at a fixed rate of 3.22% per annum, and is due and payable on March 1, 2024. There is no amortization of these notes prior to their maturity date and interest is payable quarterly.

Industrial Revenue Bonds

We have been expanding our office and distribution facility at our Kansas City, Kansas location and financed the expansion of this facility under two Industrial Revenue Bonds ('IRBs') with an aggregate principal amount of $19.0. We subsequently purchased 100% of the outstanding bonds under the IRBs at par and under the IRB debt agreement, we have the right of offset. Accordingly, the impact of the IRB has been reflected as a non-cash transaction in the Condensed Consolidated Statement of Cash Flows for the three months ended March 31, 2019. The purchase of the $19.0 of outstanding IRBs is included in other assets and the $19.0 debt obligation is included in long-term debt on the Condensed Consolidated Balance Sheet as of March 31, 2019.