Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Cash Flows [Abstract]
Cash and cash equivalents at beginning of year	$ 1,137,303	$ 2,269,756
Cash flows from operating activities:
Net income	138,925	62,657
Adjustments to reconcile net income to cash flows from operating activities:
Depreciation and amortization	50,330	45,070
Gain on acquisition	0	(7,433)
Stock-based compensation	2,869	5,046
Equity in net income of unconsolidated investments (net of tax)	(20,677)	(21,171)
Dividends received from unconsolidated investments and nonmarketable securities	25,462	2,551
Pension and postretirement benefit	(890)	(26)
Pension and postretirement contributions	(3,548)	(2,891)
Unrealized gain on investments in marketable securities	(393)	(873)
Loss on early extinguishment of debt	0	52,801
Deferred income taxes	29,067	1,363
Working capital changes	(95,050)	(63,325)
Other, net	(4,541)	8,816
Net cash provided by operating activities	121,554	82,585
Cash flows from investing activities:
Acquisitions, net of cash acquired	0	(27,742)
Capital expenditures	(131,815)	(54,143)
Sales of marketable securities, net	10	492
Repayments from joint ventures	0	1,250
Investments in equity and other corporate investments	(735)	0
Net cash used in investing activities	(132,540)	(80,143)
Cash flows from financing activities:
Repayments of long-term debt	0	(751,209)
Other (repayments) borrowings, net	(381,159)	66,384
Fees related to early extinguishment of debt	0	(46,959)
Dividends paid to shareholders	(35,382)	(34,330)
Dividends paid to noncontrolling interests	(7,378)	0
Repurchases of common stock	0	(250,000)
Proceeds from exercise of stock options	646	2,170
Withholding taxes paid on stock-based compensation award distributions	(15,009)	(7,855)
Net cash used in financing activities	(438,282)	(1,021,799)
Net effect of foreign exchange on cash and cash equivalents	4,153	4,137
Decrease in cash and cash equivalents	(445,115)	(1,015,220)
Cash and cash equivalents at end of period	$ 692,188	$ 1,254,536