Accounts Receivable (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accounts receivable
Billed accounts receivable	$ 153,011	$ 154,484
Unbilled - scheduled billings	29,993	31,258
Costs and estimated earnings in excess of billings	8,713	16,267
Accounts receivable, gross	191,717	202,009
Less allowance for doubtful accounts	(2,335)	(1,752)	(1,422)
Accounts receivable, net	189,382	200,257
Activity in the allowance for doubtful accounts
Balance at beginning of period	1,752	1,422	7,367
Additions Charge to cost and expense	1,813	825	337
Deductions Write-offs	(1,312)	(580)	(6,280)
Effect of foreign exchange rate changes	82	85	(2)
Balance at end of period	$ 2,335	$ 1,752	$ 1,422