Supplemental Consolidated Balance Sheet and Statement of Operations Information - Other Income and (Expense), Net (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Other Nonoperating Income (Expense) [Abstract]
Interest income	$ 62	$ 12	$ 145	$ 27
Income from training reimbursement program	230	206	663	272
Other	(14)	(27)	46	(174)
Nonoperating income (expense)	$ 278	$ 191	$ 854	$ 125