Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Apr. 30, 2012	Apr. 30, 2011
OPERATING ACTIVITIES:
Net income	$ 19,023	$ 15,716
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	2,892	1,985
Change in fair value of acquisition-related contingent consideration	(253)	31
Earnings of equity investee	24	1
Deferred income taxes	(477)	845
Share-based compensation expense	525	392
Change in operating assets and liabilities:
Accounts receivable	2,105	(10,468)
Inventories	97	(1,833)
Prepaid expense and other assets	(1,793)	(1,117)
Operating liabilities	6,077	5,463
Other operating activities, net	(8)	(7)
Net cash provided by operating activities	28,212	11,008
INVESTING ACTIVITIES:
Capital expenditures	(4,900)	(3,585)
Payments related to business acquisitions, net of cash acquired	(1,867)	(8)
Sales of short-term investments	0	500
Other investing activities, net	(58)	(264)
Net cash used in investing activities	(6,825)	(3,357)
FINANCING ACTIVITIES:
Dividends paid	(3,806)	(3,254)
Other financing activities, net	103	100
Net cash used in financing activities	(3,703)	(3,154)
Effect of exchange rate changes on cash	10	65
Net increase (decrease) in cash and cash equivalents	17,694	4,562
Cash and cash equivalents at beginning of year	25,842	37,563
Cash and cash equivalents at end of year	$ 43,536	$ 42,125