Debt - Schedule of Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Schedule Of Long Term Debt And Short Term Debt Instruments [Line Items]
Finance leases and other debt	$ 522	$ 456
Unamortized debt issuance costs	(218)	(288)
Total long-term debt and finance leases	55,304	55,168
Less: Current maturities of long-term debt and finance leases	96	80
Long-term debt	55,208	55,088
Unsecured senior notes
Schedule Of Long Term Debt And Short Term Debt Instruments [Line Items]
Unsecured senior notes	55,000	55,000
Wells Fargo revolving credit facility
Schedule Of Long Term Debt And Short Term Debt Instruments [Line Items]
Total Short-Term Debt	$ 56,825	$ 54,613