Retirement Plans (Tables)

6 Months Ended

Jun. 30, 2017

Retirement Benefits [Abstract]

Summary of Net Periodic Pension Expense for ACS Retirement Plan

The following table presents the net periodic pension expense for the ACS Retirement Plan for the three and six-month periods ended June 30, 2017 and 2016:

	Three Months Ended June 30,						Six Months Ended June 30,
	2017			2016			2017			2016
Interest cost	$	156		$	168		$	312		$	335
Expected return on plan assets		(185	)		(181	)		(370	)		(362	)
Amortization of loss		183			230			366			461
Net periodic pension expense	$	154		$	217		$	308		$	434