Note 3 - Acquisitions - Preliminary Price Allocation (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Jun. 01, 2018	Dec. 31, 2017
Goodwill	$ 805,284	$ 764,655		$ 721,523
Selmec [Member]
Accounts receivable			$ 14,302
Inventories			8,000
Prepaid expense and other assets			4,323
Property and equipment			5,572
Intangible assets			33,631
Goodwill			46,196
Deferred income taxes			3,252
Other assets			597
Total assets acquired			115,873
Accounts payable			7,216
Accrued wages and employee benefits			397
Other accrued liabilities			13,671
Deferred income taxes			10,974
Other long-term liabilities			3,643
Net assets acquired			$ 79,972