Summary of Significant Accounting Policies - Revenue by Contract Type (Details)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Schedule of Revenue by External Customer [Line Items]
Revenue by percent	100.00%	100.00%	100.00%
Time-and-material [Member]
Schedule of Revenue by External Customer [Line Items]
Revenue by percent	88.80%	90.30%	91.00%
Progress Billing [Member]
Schedule of Revenue by External Customer [Line Items]
Revenue by percent	8.80%	7.90%	7.30%
Percentage-of-completion [Member]
Schedule of Revenue by External Customer [Line Items]
Revenue by percent	2.40%	1.80%	1.70%