Employee Benefit Obligations - Net Funded Status (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019
Change in Benefit Obligation
Projected benefit obligation at beginning of year	$ 15,685	$ 12,249
Interest cost	37	114
Company service cost	1,483	932
Employee contributions	870	599
Prior service cost	0	0
Benefits paid	1,612	(109)
Actuarial loss	3,066	1,900
Projected benefit obligation at end of year	22,753	15,685
Change in Plan Assets
Fair value of plan assets at beginning of year	12,356	9,936
Actual return on plan assets	1,938	1,031
Employer contributions	1,306	899
Employee contributions	870	599
Benefits paid	1,612	(109)
Fair value of plan assets at end of year	18,082	12,356
Funded Status at End of year
Excess of obligation over assets			$ 4,671	$ 3,329
Change in Accrued Benefit Liability
Accrued benefit liability at beginning of year	(3,329)	(2,313)
Company contributions made during year	1,306	899
Net periodic benefit cost for year	(1,909)	(1,024)
Net decrease (increase) in accumulated other comprehensive loss	(739)	(891)
Accrued benefit liability at end of year	(4,671)	(3,329)
Non-current plan assets			18,083	12,357
Non-current liability			22,754	15,686
Accrued benefit liability at end of year	$ (3,329)	$ (3,329)	(4,671)	(3,329)
Projected Benefit Payments
Projected year 1			1,804	270
Projected year 2			394	1,434
Projected year 3			400	255
Projected year 4			788	260
Projected year 5			405	571
Projected years 6-10			$ 3,445	$ 2,109