CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Apr. 30, 2017	Apr. 30, 2016
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 20,749	$ 14,120
Adjustments to reconcile net income to net cash provided by operating activities
Stock option compensation expense	1,112	659
Depreciation	572	434
Amortization of purchased intangibles	183	321
Deferred income tax expense	263	1,897
Other	(382)	(128)
Changes in operating assets and liabilities
Accounts receivable	(16,428)	(6,713)
Prepaid expenses and other assets	(1,773)	(1,408)
Accounts payable and accrued expenses	12,730	5,786
Billings in excess of costs and estimated earnings, net	23,938	28,758
Net cash provided by operating activities	40,964	43,726
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of short-term investments	(185,000)	(50,000)
Maturities of short-term investments	145,000	36,000
Purchases of property, plant and equipment	(1,863)	(245)
Net cash used in investing activities	(41,863)	(14,245)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the exercise of stock options	867	495
Net cash provided by financing activities	867	495
EFFECTS OF EXCHANGE RATE CHANGES ON CASH	181	545
NET INCREASE IN CASH AND CASH EQUIVALENTS	149	30,521
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	167,198	160,909
CASH AND CASH EQUIVALENTS, END OF PERIOD	$ 167,347	191,430
SUPPLEMENTAL CASH FLOW INFORMATION
Cash paid for income taxes		$ 847