Condensed Consolidated Statements of Comprehensive Income (Parenthetical) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Increase in estimated fair value of investment in debt securities, tax expense (benefit)	$ 0	$ (736)	$ 0	$ (4,044)
Unrecognized actuarial loss and prior service cost, tax expense (benefit)	235	113	1,760	(196)
Foreign currency translation adjustments, tax	(696)	0	(82)	0
Income tax on cash flow hedge activity	$ 38	$ 48	$ 112	$ 127