CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Noncontrolling Interests	Total
Balances at Jan. 31, 2013	$ 2,096	$ 94,971	$ 23,850		$ (1,749)	$ 119,168
Balances (in shares) at Jan. 31, 2013	13,974,327
Net income			40,125		3,219	43,344
Exercise of stock options	$ 46	3,722				$ 3,768
Exercise of stock options (in shares)	309,074					309,074
Stock option vesting		1,536				$ 1,536
Release of restricted stock	$ 1	25				26
Release of restricted stock (in shares)	2,500
Excess tax benefit on exercised stock options		576				576
Cash dividends			(10,640)			(10,640)
Deconsolidation of VIEs					(1)	(1)
Balances at Jan. 31, 2014	$ 2,143	100,830	53,335		1,469	157,777
Balances (in shares) at Jan. 31, 2014	14,285,901
Net income			30,445		13,010	43,455
Exercise of stock options	$ 52	5,336				$ 5,388
Exercise of stock options (in shares)	345,300					345,300
Stock option vesting		2,017				$ 2,017
Excess tax benefit on exercised stock options		1,480				1,480
Cash dividends			(10,166)			(10,166)
Cash distributions to joint venture partner					(25,000)	(25,000)
Formation of VIE					1	1
Balances at Jan. 31, 2015	$ 2,195	109,663	73,614		(10,520)	174,952
Balances (in shares) at Jan. 31, 2015	14,631,201
Net income			36,345		13,859	50,204
Foreign currency translation loss				$ (565)		(565)
Acquisition of APC	$ 15	3,521				3,536
Acquisition of APC (in shares)	98,818
Exercise of stock options	$ 16	1,802				$ 1,818
Exercise of stock options (in shares)	106,450					106,450
Stock option vesting		2,374				$ 2,374
Excess tax benefit on exercised stock options		(86)				(86)
Cash dividends			(10,378)			(10,378)
Balances at Jan. 31, 2016	$ 2,226	$ 117,274	$ 99,581	$ (565)	$ 3,339	$ 221,855
Balances (in shares) at Jan. 31, 2016	14,836,469