Shareholder's Equity and Stock-Based Compensation - Summary of Stock-Based Compensation Expense Recognized in Statements of Operations Related to All Outstanding Stock Based Compensation Awards (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 1,034	$ 1,009
Direct Costs, Excluding Depreciation and Amortization
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	542	563
Selling, General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 492	$ 446