Note 11 - Schedule of Treasury Stock, at Cost (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended
		Jul. 31, 2016		Jun. 30, 2016		May 31, 2016		Jul. 31, 2015
Balance as of April 30, 2016 (1)(2) (in shares)	[1],[2]	243,411
Balance as of April 30, 2016 (1)(2)	[1],[2]	$ 3,040
Balance as of April 30, 2016 (1)(2) (in dollars per share)	[1],[2]	$ 12.49
Balance as of April 30, 2016 (1)(2)	[1],[2]	$ 1,350
Treasury Stock, Shares, Acquired	[2]			19,539		7,820		5,355
Treasury Stock, Value, Acquired, Cost Method		(535)		$ 313	[2]	$ 132	[2]	$ (166)	[2]
May 31, 2016 (2) (in dollars per share)	[2]			$ 16.05		$ 16.90		$ 16.85
May 31, 2016 (2)	[2]	$ 1,350	[1]	$ 905		$ 1,218
Balance as of July 31, 2016 (in shares)		276,125
Balance as of July 31, 2016		$ 3,575
Balance as of July 31, 2016 (in dollars per share)		$ 12.95
Balance as of July 31, 2016	[2]	$ 815		$ 905		$ 1,218

[1] Includes 85,219 shares with a total average cost of $1,036,000 that were acquired during the former repurchase program, which was authorized in January 2011 and expired in January 2012; 18,400 shares were acquired prior to the repurchase program authorized in January 2011.

[2] Were acquired during the $3 million repurchase program authorized in September 2012.