Employee Benefit Plans - Pension Expense (Details) - Pension [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Net periodic benefit cost
Service cost	$ 23	$ 2
Interest cost	605	586
Expected return on plan assets	(626)	(719)
Amortization of prior service cost	26	(36)
Amortization of net (gain) loss	415	463
Net periodic benefit cost	$ 443	$ 296