Pension and Non-pension Post-retirement Benefits

We have pension plans covering the majority of our employees. Benefits generally are based on compensation and service for salaried employees and job grade and length of service for hourly employees. In addition, we have an unfunded supplemental employee retirement plan (SERP) that covers certain salaried U.S.-based employees of Libbey hired before January 1, 2006. The U.S. pension plans cover the salaried U.S.-based employees of Libbey hired before January 1, 2006, and most hourly U.S.-based employees (excluding employees hired at Shreveport after December 15, 2008, and at Toledo after September 30, 2010). Effective January 1, 2013, we ceased annual company contribution credits to the cash balance accounts in our Libbey U.S. Salaried Pension Plan and SERP. The non-U.S. pension plans cover the employees of our wholly owned subsidiary in Mexico and are unfunded.

The components of our net pension expense, including the SERP, are as follows:



Three months ended September 30,	U.S. Plans						Non-U.S. Plans						Total
(dollars in thousands)	2018			2017			2018			2017			2018			2017
Service cost	$	1,003		$	979		$	289		$	286		$	1,292		$	1,265
Interest cost	3,154			3,445			755			725			3,909			4,170
Expected return on plan assets	(5,665		)	(5,619		)	—			—			(5,665		)	(5,619		)
Amortization of unrecognized:
Prior service cost (credit)	—			59			(51		)	(54		)	(51		)	5
Actuarial loss	1,618			1,308			158			156			1,776			1,464
Pension expense	$	110		$	172		$	1,151		$	1,113		$	1,261		$	1,285

Nine months ended September 30,	U.S. Plans						Non-U.S. Plans						Total
(dollars in thousands)	2018			2017			2018			2017			2018			2017
Service cost	$	3,007		$	2,937		$	865		$	814		$	3,872		$	3,751
Interest cost	9,461			10,337			2,259			2,063			11,720			12,400
Expected return on plan assets	(16,994		)	(16,859		)	—			—			(16,994		)	(16,859		)
Amortization of unrecognized:
Prior service cost (credit)	1			177			(152		)	(153		)	(151		)	24
Actuarial loss	4,854			3,925			471			446			5,325			4,371
Pension expense	$	329		$	517		$	3,443		$	3,170		$	3,772		$	3,687

We have contributed $0.9 million and $2.1 million of cash to our pension plans for the three months and nine months ended September 30, 2018, respectively. Pension contributions for the remainder of 2018 are estimated to be $1.3 million.

We provide certain retiree healthcare and life insurance benefits covering our U.S. and Canadian salaried employees hired before January 1, 2004, and a majority of our union hourly employees (excluding employees hired at Shreveport after December 15, 2008, and at Toledo after September 30, 2010). Employees are generally eligible for benefits upon retirement and completion of a specified number of years of creditable service. Benefits for most hourly retirees are determined by collective bargaining. The U.S. non-pension, post-retirement plans cover the hourly and salaried U.S.-based employees of Libbey (excluding those mentioned above). The non-U.S., non-pension, post-retirement plans cover the retirees and active employees of Libbey who are located in Canada. The post-retirement benefit plans are unfunded.

The provision for our non-pension, post-retirement, benefit expense consists of the following:



Three months ended September 30,	U.S. Plans						Non-U.S. Plans						Total
(dollars in thousands)	2018			2017			2018			2017			2018			2017
Service cost	$	151		$	157		$	1		$	—		$	152		$	157
Interest cost	456			526			9			10			465			536
Amortization of unrecognized:
Prior service (credit)	(71		)	(50		)	—			—			(71		)	(50		)
Actuarial (gain)	(52		)	(65		)	(16		)	(13		)	(68		)	(78		)
Non-pension post-retirement benefit expense	$	484		$	568		$	(6	)	$	(3	)	$	478		$	565

Nine months ended September 30,	U.S. Plans						Non-U.S. Plans						Total
(dollars in thousands)	2018			2017			2018			2017			2018			2017
Service cost	$	453		$	473		$	1		$	1		$	454		$	474
Interest cost	1,367			1,578			29			32			1,396			1,610
Amortization of unrecognized:
Prior service (credit)	(212		)	(151		)	—			—			(212		)	(151		)
Actuarial (gain)	(157		)	(194		)	(49		)	(39		)	(206		)	(233		)
Non-pension post-retirement benefit expense	$	1,451		$	1,706		$	(19	)	$	(6	)	$	1,432		$	1,700

Our 2018 estimate of non-pension cash payments is $4.3 million, of which we have paid $1.3 million and $3.2 million for the three months and nine months ended September 30, 2018, respectively.