Employee Benefit Plans - Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Summary of employee benefits charged to operating expenses
Payroll taxes	$ 256	$ 261	$ 871	$ 913
Medical plans	432	490	1,359	1,650
401k match and profit sharing	349	261	929	684
Periodic pension cost	358	470	1,073	1,280
Other	15	12	40	37
Total employee benefits	$ 1,410	$ 1,494	$ 4,272	$ 4,564