In millions
	March 31, 2020		December 31, 2019
$1.2 billion Senior Credit Facility, due in 2022	$	774.0	$	758.7
$1.3 billion Term Loan, due in 2022		1,128.3		1,172.2
$600 million Senior Notes, due 2024		600.0		600.0
Promissory notes and deferred consideration weighted average maturity 2.3 years at 2020 and 2.5 years at 2019		66.2		73.1
Foreign bank debt weighted average maturity 1.4 years at 2020 and 1.6 years at 2019		37.3		42.2
Obligations under finance leases		28.9		30.4
Total debt		2,634.7		2,676.6
Less: current portion of total debt		101.4		103.1
Less: unamortized debt issuance costs		14.5		14.2
Long-term portion of total debt	$	2,518.8	$	2,559.3

The estimated fair value of our debt approximated $2.63 billion and $2.73 billion as of March 31, 2020 and December 31, 2019, respectively. These fair value amounts were estimated using an income approach by applying market interest rates for comparable instruments and developed based on inputs classified as Level 2 within the fair value hierarchy.

On February 25, 2020, the Company executed a Fifth Amendment which amended the Credit Agreement to, among other things:

In the three months ended March 31, 2020 and in connection with the Fifth Amendment, the Company incurred issuance costs of $1.7 million, of which $0.3 million has been charged to Interest expense, net. The remainder was capitalized as unamortized debt issuance costs and is being amortized to Interest expense, net over the remaining term of the Credit Agreement.

The Company may make prepayments against the amended Senior Credit Facility, in whole or in part, without premium or penalty. The Company would be required to prepay certain outstanding amounts in the event of certain circumstances or transactions. In April 2020, with the net proceeds generated from the divestiture of the Domestic Environmental Solutions business, the Company made principal repayments of approximately $430.0 million, which excludes certain transaction costs, final working capital adjustments, or other adjustments associated with the divestiture.

As of March 31, 2020, the Company was in compliance with its Consolidated Leverage Ratio covenant, with an actual ratio of 4.50 to 1.00, which was below the allowed maximum ratio of 5.00 to 1.00 as set forth in the Fifth Amendment. On April 6, 2020, the Company completed the divestiture of the Domestic Environmental Solutions business. Therefore, effective April 6, 2020, the Consolidated Leverage Ratio will be decreased by 0.25 to 4.75 to 1.00 for fiscal quarters ending on or before December 31, 2021 and 4.25 to 1.00 for fiscal quarters ending on or after March 31, 2022.

Due to COVID-19 and related uncertainty of its impacts on future operating results, it is reasonably likely that the Company could exceed this Consolidated Leverage Ratio threshold at some point in the next 12 months. This risk can be mitigated and potentially managed through appropriate spending controls, divestitures, restructuring the Company’s existing indebtedness, amending the Credit Agreement, or seeking temporary relief from the Consolidated Leverage Ratio covenant from the Company’s lenders.

A failure to comply with these provisions could result in an event of default. Upon an event of default, unless waived, the lenders could elect to terminate their commitments, cease making further loans, and/or cause their loans to become due and payable in full, foreclose against any assets securing the debt under our Credit Agreement and force us and our subsidiaries into bankruptcy or liquidation.

Amounts committed to outstanding letters of credit, the unused portion of the Company’s Senior Credit Facility and other letters of credit outstanding at were as follows:

In millions
	March 31, 2020		December 31, 2019
Outstanding letters of credit under Senior Credit Facility	$	29.0	$	33.0
Unused portion of the Senior Credit Facility		397.0		408.3