Employee Benefit Plans - Pension Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Net periodic benefit cost
Employer contributions	$ 600	$ 600
Pension [Member]
Net periodic benefit cost
Service cost	19	23
Interest cost	498	605
Expected return on plan assets	(644)	(626)
Amortization of prior service cost	26	26
Amortization of net (gain) loss	432	415
Net periodic benefit cost	$ 331	$ 443