Condensed Consolidated Statements of Comprehensive Income (Parenthetical) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Statement of Comprehensive Income [Abstract]
Increase in estimated fair value of investment in debt securities, tax expense (benefit)	$ 0	$ (1,350)	$ 0	$ (3,308)
Unrecognized actuarial loss and prior service cost, tax expense (benefit)	1,289	(422)	1,525	(309)
Foreign currency translation adjustments, tax	0	0	613	0
Income tax on cash flow hedge activity	$ 39	$ 38	$ 74	$ 80