Note 7 - Investments - Amount of the Asbestos Litigation Liability (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($)
Amended PCC Plan [Member]
Fair Value of Asbestos Litigation Liability	$ 678,000
Contribution of PCC & PCE Equity Interests - Carrying Value	(182,000)
Gain on Contribution of Equity Interests	(56,000)
Other adjustments	(1,000)
Asbestos Litigation Liability as of December 31, 2016	439,000
Amended PCC Plan [Member] | Equity Interests [Member]
Fair Value of Asbestos Litigation Liability	238,000
Contribution of PCC & PCE Equity Interests - Carrying Value	(182,000)
Gain on Contribution of Equity Interests	(56,000)
Other adjustments
Asbestos Litigation Liability as of December 31, 2016	0
Amended PCC Plan [Member] | Fixed Series of Payments [Member]
Fair Value of Asbestos Litigation Liability	290,000
Contribution of PCC & PCE Equity Interests - Carrying Value
Gain on Contribution of Equity Interests
Other adjustments
Asbestos Litigation Liability as of December 31, 2016	290,000
Non-PCC Asbestos Litigation [Member]
Fair Value of Asbestos Litigation Liability	150,000
Contribution of PCC & PCE Equity Interests - Carrying Value
Gain on Contribution of Equity Interests
Other adjustments	(1,000)
Asbestos Litigation Liability as of December 31, 2016	$ 149,000