Supplementary Balance Sheet Information - Accumulated Other Comprehensive Income (Details)	3 Months Ended
	Mar. 31, 2017 USD ($)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ 2,099,920,000
Ending Balance	2,144,730,000
Reclassifications of AOCI	0
Foreign currency translation adjustments and transfers from noncontrolling interests
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(65,482,000)
Pretax Amount	6,052,000
Tax Effect	540,000
Net-of-Tax Amount	5,512,000
Ending Balance	(59,970,000)
Unrealized gain on available-for-sale securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	9,862,000
Pretax Amount	(2,880,000)
Tax Effect	(1,021,000)
Net-of-Tax Amount	(1,859,000)
Ending Balance	8,003,000
Change in AOCI related to postretirement healthcare plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(538,000)
Pretax Amount	194,000
Tax Effect	70,000
Net-of-Tax Amount	124,000
Ending Balance	(414,000)
Accumulated Other Comprehensive Income (Loss) (OCI)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(56,158,000)
Pretax Amount	3,366,000
Tax Effect	(411,000)
Net-of-Tax Amount	3,777,000
Ending Balance	$ (52,381,000)