Accrued Payroll and Employee Benefits Accrued Payroll and Employee Benefits - Severance Cost Schedule (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Restructuring Reserve [Roll Forward]
Balance, beginning of period	$ 285	$ 1,440
Adjustments to expense	134	1,190
Payments	(306)	(998)
Balance, end of period	$ 113	$ 1,632