Postretirement Benefit Obligations (Tables)

3 Months Ended

Mar. 31, 2018

Retirement Benefits [Abstract]

Schedule of Net Benefit Costs

The components of net periodic benefit cost of the Company’s pension plan are as follows:

	Three Months Ended March 31,
	2018			2017
Service costs	$	2,001		$	1,908
Interest costs	469			333
Expected return on plan assets	(287		)	(76		)
Net periodic benefit cost	$	2,183		$	2,165