Note 18 - Quarterly Results of Operations (Unaudited) - Quarterly Results of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																12 Months Ended
	Jun. 30, 2018		Mar. 31, 2018		Dec. 31, 2017		Sep. 30, 2017		Jun. 30, 2017		Mar. 31, 2017		Dec. 31, 2016		Sep. 30, 2016		Jun. 30, 2018		Jun. 30, 2017		Jun. 30, 2016
Net sales	$ 227,508		$ 216,743		$ 209,751		$ 214,379		$ 217,089		$ 184,715		$ 173,854		$ 179,600		$ 868,382	[1]	$ 755,258	[1]	$ 751,586	[1]
Gross profit	82,320		73,772		71,526		74,181		72,736		61,348		56,894		61,776		301,801		252,754		252,253
Net income	$ 12,610		$ 12,800		$ (2,807)		$ 13,998		$ 14,131		$ 7,660		$ 10,442		$ 14,344		$ 36,604		$ 46,545		$ 52,056
Basic (in dollars per share)	$ 0.99	[2]	$ 1.01	[2]	$ (0.22)	[2]	$ 1.10	[2]	$ 1.12	[2]	$ 0.60	[2]	$ 0.82	[2]	$ 1.13	[2]	$ 2.88		$ 3.68		$ 4.11
Diluted (in dollars per share)	$ 0.99	[2]	$ 1	[2]	$ (0.22)	[2]	$ 1.10	[2]	$ 1.11	[2]	$ 0.60	[2]	$ 0.82	[2]	$ 1.12	[2]	$ 2.86		$ 3.65		$ 4.08

[1] Net sales were identified based on geographic location where our products and services were initiated.

[2] Basic and diluted earnings per share are computed independently for each reporting period. Accordingly, the sum of the quarterly earnings per share amounts may not agree to the year-to-date amounts.