Employee Benefits

The components of net periodic benefit costs related to pension benefits are as follows:



	Three Months Ended March 31,
	2019						2018
	U.S Plans			Non-U.S. Plans			U.S Plans			Non-U.S. Plans
	(In thousands)
Service cost	$	753		$	389		$	887		$	651
Interest cost	1,938			533			1,795			541
Expected return on plan assets	(2,517		)	(633		)	(2,452		)	(700		)
Amortization of prior service cost	—			9			1,235			3
Amortization of net actuarial loss	845			106			—			168
Net periodic benefit cost	$	1,019		$	404		$	1,465		$	663

The components of net periodic benefit costs other than the service cost component are included in Other expense on our Condensed Consolidated Statements of Operations.

We made contributions of $3.4 million and $4.6 million to our pension plans in the three months ended March 31, 2019 and 2018, respectively.

The components of net periodic benefit cost related to other post-retirement benefits are as follows:



	Three Months Ended March 31,
	2019			2018
	U.S Plans			U.S Plans
	(In thousands)
Service cost	$	90		$	155
Interest cost	240			335
Amortization of prior service cost	(437		)	188
Amortization of net actuarial loss	175			—
Net periodic benefit cost	$	68		$	678

During the year ended December 31, 2018, we amended the post-retirement benefits plan for post-65 retirees to provide an annual subsidy based on years of service. The annual subsidy replaces a company-sponsored medical plan. This plan modification resulted in a $13.1 million reduction in pension and other post-retirement liabilities during the year ended December 31, 2018.

The components of net periodic benefit costs other than the service cost component are included in Other expense on our Condensed Consolidated Statements of Operations.