	March 29,			December 31,
	2019			2018
Senior Credit Facilities – term loan	$	2,300		$	4,600
Less: unamortized debt issuance costs		(60	)		(65	)
Total current portion of long-term debt	$	2,240		$	4,535

Senior Credit Facilities – term loan	$	67,625		$	69,925
Senior Credit Facilities – revolving credit facility		132,480			135,058
Less: unamortized debt issuance costs		(1,902	)		(2,140	)
Total long-term debt	$	198,203		$	202,843

Total Senior Credit Facilities	$	200,443		$	207,378

In August 2017, the Company entered into an amendment (the “Third Amendment”) to the second amended and restated credit agreement, dated as of May 19, 2016 (the “Second Amended and Restated Credit Agreement”). The Third Amendment increased the revolving credit facility under the Second Amended and Restated Credit Agreement by $100 million, from $225 million to $325 million, and reset the uncommitted accordion feature to $125 million for potential future expansion. Additionally, the Third Amendment increased the term loan balance from $65.6 million to $90.6 million. Under the Third Amendment, the Company is required to pay quarterly scheduled principal repayments of $2.3 million beginning in October 2017, with the final installment of $56.1 million due upon maturity in May 2021.

In February 2018, the Company entered into a fourth amendment (the “Fourth Amendment”) to the Second Amended and Restated Credit Agreement. The Fourth Amendment increased the maximum consolidated leverage ratio from 3.00 to 3.50, increased the maximum consolidated leverage ratio for permitted acquisitions and stock repurchases from 2.50 to 3.00, increased the maximum consolidated leverage ratio for a designated acquisition from 3.00 to 3.50, and increased the maximum consolidated leverage ratio for four consecutive quarters following a designated acquisition from 3.50 to 4.00. The Fourth Amendment also made certain other technical changes to the Second Amended and Restated Credit Agreement.

The Company is required to satisfy certain financial and non-financial covenants under the Second Amended and Restated Credit Agreement. The Second Amended and Restated Credit Agreement also contains customary events of default. The Company was in compliance with these covenants as of March 29, 2019.

The Company’s obligations under the Senior Credit Facilities are secured, on a senior basis, by a lien on substantially all of the assets of Novanta Inc., Novanta Corporation, NDS Surgical Imaging LLC, Novanta Europe GmbH, Novanta UK Investments Holding Limited and Novanta Technologies UK Limited. The Second Amended and Restated Credit Agreement also contains customary events of default.

As of March 29, 2019 and December 31, 2018, the outstanding balance of the Company’s debt approximated its fair value based on current rates available to the Company for debt of similar maturities. The fair value of the Company’s debt is classified as Level 2 under the fair value hierarchy.