Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
OPERATING ACTIVITIES
Net income	$ 12,339	$ 16,108
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	10,172	9,914
Interest accretion of convertible notes discount	2,587	2,391
Employee share-based compensation expense	3,957	2,564
Financing costs amortization	326	326
Unrealized foreign currency transaction loss	1,072	346
Other non-cash operating activities	118	433
Changes in asset and liabilities, net of acquisitions:
Accounts receivable	44,543	(16,892)
Inventory	(12,144)	(15,704)
Unbilled contract revenues and other assets	(28,844)	(15,224)
Accounts payable and other liabilities	(20,392)	(8,764)
Customer advances and billings in excess of contract revenue	7,127	864
Net Cash Provided by (Used In) Operating Activities	20,861	(23,638)
INVESTING ACTIVITIES
Capital expenditures	(10,417)	(12,078)
Advance payment on acquisition	(4,624)	0
Proceeds from sale of assets	34	0
Net Cash Used In Investing Activities	(15,007)	(12,078)
FINANCING ACTIVITIES
Borrowings on revolving credit facilities	3,283	48,978
Repayments on revolving credit facilities	(3,252)	(31,738)
Principal payments on long-term debt	(938)	(938)
Proceeds from exercise of stock options	516	3,913
Excess tax benefit from share-based compensation	1,564	4,383
Common stock repurchases	(3,174)	(1,879)
Net Cash (Used In) Provided By Financing Activities	(2,001)	22,719
Effect of exchange rate changes on cash	(779)	(2,233)
Net increase (decrease) in cash and cash equivalents	3,074	(15,230)
Cash and cash equivalents at beginning of period	137,345	141,498
CASH AND CASH EQUIVALENTS AT END OF PERIOD	$ 140,419	$ 126,268