Supplemental Balance Sheet, Income Statement and Cash Flow Information - Accumulated Other Comp Inc (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period	$ 3,247,025
Other comprehensive income (loss), net of tax	783	$ 34,329
Balance at the end of the period	3,177,948
Accumulated Other Comprehensive Income
Changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period	(12,119)	(47,593)
Other comprehensive income (loss) before reclassifications, net of tax	659	34,131
Amounts reclassified from accumulated other comprehensive income (loss)	124	198
Other comprehensive income (loss), net of tax	783	34,329
Balance at the end of the period	(11,336)	(13,264)
Gains (losses) on cash flow hedges
Changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period	(1,296)	(1,670)
Amounts reclassified from accumulated other comprehensive income (loss)	93	93
Other comprehensive income (loss), net of tax	93	93
Balance at the end of the period	(1,203)	(1,577)
Unrealized gains (losses) on available-for-sale securities.
Changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period	14,235	(314)
Other comprehensive income (loss) before reclassifications, net of tax	(3,201)	769
Other comprehensive income (loss), net of tax	(3,201)	769
Balance at the end of the period	11,034	455
Defined benefit pension plan items
Changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period	(3,760)	(6,568)
Amounts reclassified from accumulated other comprehensive income (loss)	31	105
Other comprehensive income (loss), net of tax	31	105
Balance at the end of the period	(3,729)	(6,463)
Foreign currency items
Changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period	(21,298)	(39,041)
Other comprehensive income (loss) before reclassifications, net of tax	3,860	33,362
Other comprehensive income (loss), net of tax	3,860	33,362
Balance at the end of the period	$ (17,438)	$ (5,679)