Note 12 - Mergers and Acquisitions - Purchase Price Allocation (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Nov. 30, 2017	Jun. 30, 2016	Mar. 31, 2016	May 18, 2015
Goodwill	$ 147,515			$ 0
O-Tex [Member]
Current assets		$ 45,895
Property and equipment		64,496
Goodwill		147,515
Other intangible assets		71,500
Total assets acquired		329,406
Current liabilities		17,442
Deferred income taxes		31,301
Other liabilities		8,746
Total liabilities assumed		57,489
Net assets acquired		$ 271,917
ESPCT [Member]
Current assets					$ 5,822
Property and equipment					2,529
Goodwill					24,219
Other intangible assets					5,173
Total assets acquired					37,743
Current liabilities					1,927
Deferred income taxes					2,067
Other liabilities					276
Total liabilities assumed					4,270
Net assets acquired			$ 33,500		$ 33,473