Note 5 - Share Repurchase Program (Details Textual) - USD ($)	3 Months Ended			6 Months Ended	9 Months Ended
	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Jun. 30, 2016	Dec. 31, 2015	Nov. 04, 2015	Dec. 31, 2007
Stock Repurchase Program, Number of Shares Authorized to be Repurchased						2,000,000	1,000,000
Stock Repurchase Program, Authorized Amount						$ 40,000,000
Stock Repurchased and Retired During Period, Shares		455,581	941,024
Stock Repurchased and Retired During Period, Value	$ 0	$ 7,500,000	$ 16,200,000	$ 7,513,000	$ 16,175,000