Employee Benefit Obligations - Net Funded Status (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Change in Benefit Obligation
Projected benefit obligation at beginning of year	$ 10,317	$ 8,241
Interest cost	64	54
Company service cost	820	878
Employee contributions	486	417
Prior service cost		(314)
Benefits paid	475	341
Actuarial loss	87	700
Projected benefit obligation at end of year	12,249	10,317
Change in Plan Assets
Fair value of plan assets at beginning of year	8,243	5,978
Actual return on plan assets	3	882
Employer contributions	729	625
Employee contributions	486	417
Benefits paid	475	341
Fair value of plan assets at end of year	9,936	8,243
Funded Status at End of year
Excess of obligation over assets	(2,313)	(2,074)
Change in Accrued Benefit Liability
Accrued benefit liability at beginning of year	(2,074)	(2,263)
Company contributions made during year	729	625
Net periodic benefit cost for year	(874)	(1,036)
Net decrease (increase) in accumulated other comprehensive loss	(94)	600
Accrued benefit liability at end of year	(2,313)	(2,074)
Non - current plan assets	9,936	8,243
Non - current liability	12,249	10,317
Accrued benefit liability at end of year	(2,313)	(2,074)
Projected Benefit Payments
Projected year 1	206	166
Projected year 2	205	168
Projected year 3	1,158	172
Projected year 4	195	1,124
Projected year 5	200	163
Projected year 6-10	$ 2,859	$ 1,053