Note 17 - Shareholders' Equity (Details Textual) - USD ($) $ / shares in Units, $ in Thousands							1 Months Ended	3 Months Ended				10 Months Ended	12 Months Ended
	Jul. 28, 2016	Jan. 22, 2016	Oct. 29, 2015	Mar. 04, 2014	Jan. 15, 2014	Jan. 15, 2014	May 28, 2014	Dec. 31, 2016	Jan. 22, 2016	May 28, 2014	Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Oct. 28, 2015	Oct. 26, 2015	Jul. 15, 2015	Dec. 03, 2014	Oct. 22, 2013
Preferred Stock, Par or Stated Value Per Share								$ 100					$ 100	$ 100
Stock Issued During Period, Value, Acquisitions															$ 1,915,000
Stock Issued During Period, Value, New Issues															400,000
Minimum Closing Price of Common Stock for the Company to Exercise Option to Convert Preferred Stock					$ 35
Treasury Stock, Shares, Acquired												98,100,000	197,100,000	167,000,000
Treasury Stock, Value, Acquired, Cost Method												$ 2,000,000	$ 4,244,000	$ 3,228,000	2,483,000
Payments for Repurchase of Common Stock													$ 4,227,000	$ 3,228,000	$ 2,483,000
Oct. 22, 2013 [Member]
Stock Repurchase Program, Authorized Amount																				$ 2,000,000
March 4, 2014 [Member] | Citibank [Member]
Stock Repurchase Program, Authorized Amount				$ 1,250,000
Treasury Stock, Shares, Acquired				52,500,000			8,700,000			61,200,000
Accelerated Share Repurchases, Settlement (Payment) or Receipt				$ (1,250,000)
Jan. 15, 2014 [Member] | Open Market [Member]
Treasury Stock, Shares, Acquired															36,900,000
Treasury Stock, Value, Acquired, Cost Method															$ 750,000
Dec. 3, 2014 [Member]
Stock Repurchase Program, Authorized Amount, Payment Tranche One																			$ 1,500,000
July 15, 2015 [Member]
Stock Repurchase Program, Authorized Amount																		$ 2,000,000
Oct. 26, 2015 [Member]
Stock Repurchase Program, Authorized Amount																	$ 4,000,000
Oct. 28, 2015 [Member] | Morgan Stanley [Member]
Stock Repurchase Program, Authorized Amount																$ 1,250,000
Treasury Stock, Shares, Acquired		15,900,000	53,100,000						69,000,000
Accelerated Share Repurchases, Settlement (Payment) or Receipt			$ (1,250,000)
Dec. 3, 2014 & July 15, 2015 [Member]
Treasury Stock, Shares, Acquired														98,000,000
Treasury Stock, Value, Acquired, Cost Method														$ 2,000,000
July 28, 2016 [Member]
Treasury Stock, Shares, Acquired	74,400,000							12,300,000
Payments for Repurchase of Common Stock	$ 2,000,000
The 2015 Repurchase Program [Member]
Treasury Stock, Shares, Acquired													86,700,000
The 2015 Repurchase Program [Member] | Open Market [Member]
Treasury Stock, Shares, Acquired													110,000,000
Treasury Stock, Value, Acquired, Cost Method													$ 2,200,000
Common Stock [Member]
Convertible Preferred Stock, Shares Issued upon Conversion					50,000	50,000
Convertible Preferred Stock, Threshold Trading Days					25 days
Convertible Preferred Stock, Threshold Consecutive Trading Days					40 days
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Other Comprehensive Income (Loss), Equity Method Investments, Tax													20,000
Other Comprehensive Income (Loss), Tax													36,000	35,000	104,000
AOCI Attributable to Parent [Member]
Other Comprehensive Income (Loss), Tax													52,000	41,000	96,000
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Other Comprehensive Income (Loss), Tax													12,000	$ 6,000	(7,000)
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Other Comprehensive Income (Loss), Tax													1,000		$ (1,000)
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Other Comprehensive Income (Loss), Tax													$ 3,000
Samsung Corning Precision Materials Co., Ltd. [Member]
Stock Issued During Period, Value, Acquisitions						$ 2,300,000
Convertible Preferred Stock, Series A [Member]
Preferred Stock, Par or Stated Value Per Share					$ 100	$ 100
Preferred Stock, Dividend Rate, Percentage					4.25%
Convertible Preferred Stock, Series A [Member] | Samsung Corning Precision Materials Co., Ltd. [Member]
Preferred Stock, Par or Stated Value Per Share					$ 100	$ 100
Stock Issued During Period, Shares, Acquisitions					1,900	2,300					1,900
Share Price					$ 1,000,000	$ 1,000,000
Stock Issued During Period, Value, Acquisitions					$ 1,900,000
Convertible Preferred Stock, Series A [Member] | Samsung Corning Precision Materials Co., Ltd. [Member] | Additional Amount Issued at Closing [Member]
Stock Issued During Period, Value, New Issues					$ 400,000						$ 400,000