Supplemental Consolidated Balance Sheet and Statement of Operations Information - Other Income and (Expense), Net (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Other Nonoperating Income (Expense) [Abstract]
Interest income	$ 64	$ 51	$ 209	$ 78
Income from training reimbursement program	247	236	910	508
Other	(13)	(124)	33	(298)
Nonoperating income (expense)	$ 298	$ 163	$ 1,152	$ 288