CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Jan. 31, 2017	Jan. 31, 2016	Jan. 31, 2015
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 77,426	$ 50,204	$ 43,455
Adjustments to reconcile net income to net cash provided by (used in) operating activities
Impairment loss	1,979
Deferred income tax expense	1,237	3,421	896
Stock option compensation expense	2,344	2,374	2,017
Depreciation	2,043	779	551
Amortization of purchased intangibles assets	1,163	531	243
Gain on the deconsolidation of a variable interest entity		(349)
Other	517	107
Changes in operating assets and liabilities
Accounts receivable	9,217	(12,194)	(3,879)
Prepaid expenses and other assets	(668)	(2,751)	501
Accounts payable and accrued expenses	59,522	(12,196)	22,645
Billings in excess of costs and estimated earnings, net	104,264	(62,958)	26,900
Net cash provided by (used in) operating activities	259,044	(33,032)	93,329
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of short-term investments	(595,000)	(252,000)
Maturities of short-term investments	354,000	138,000
Purchase of subsidiaries, net of cash acquired (Note 3)		(17,381)
Purchases of property, plant and equipment	(2,811)	(3,118)	(2,936)
Decrease (increase) in notes receivable		3,960	(614)
Net cash used in investing activities	(243,811)	(130,539)	(3,550)
CASH FLOWS FROM FINANCING ACTIVITIES
Cash dividends	(15,260)	(10,378)	(10,166)
Cash distributions to joint venture partner	(9,500)		(25,000)
Proceeds from the exercise of stock options	15,901	1,818	5,389
Excess income tax benefits on exercised stock options (Note 2)		(86)	1,480
Net cash used in financing activities	(8,859)	(8,646)	(28,297)
EFFECTS OF EXCHANGE RATE CHANGES ON CASH	(85)	(565)
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	6,289	(172,782)	61,482
CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR	160,909	333,691	272,209
CASH AND CASH EQUIVALENTS, END OF YEAR	167,198	160,909	333,691
SUPPLEMENTAL CASH FLOW INFORMATION
Cash paid for income taxes	$ 36,861	$ 25,678	$ 18,662
Common stock issued in connection with the acquisition of APC (noncash transaction, see Note 3)		3,536