Other Comprehensive Income (Loss) - Changes in AOCI Balances by Component (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Changes in AOCI balances by component (after-tax)
BALANCE, beginning of year	$ 3,118,050	$ 3,492,399
TOTAL OTHER COMPREHENSIVE INCOME, NET OF TAX	45,069	29,622
BALANCE, end of year	3,115,925	3,129,307
Accumulated Other Comprehensive Income (Loss)
Changes in AOCI balances by component (after-tax)
BALANCE, beginning of year	(542,478)	(402,242)
Other comprehensive income before reclassifications	41,617	26,733
Amounts reclassified from AOCI	2,967	2,549
TOTAL OTHER COMPREHENSIVE INCOME, NET OF TAX	44,584	29,282
BALANCE, end of year	(497,894)	(372,960)
Foreign Currency Translation
Changes in AOCI balances by component (after-tax)
BALANCE, beginning of year	(308,747)	(211,177)
Other comprehensive income before reclassifications	41,385	26,018
Amounts reclassified from AOCI	0	0
TOTAL OTHER COMPREHENSIVE INCOME, NET OF TAX	41,385	26,018
BALANCE, end of year	(267,362)	(185,159)
Ownership Share of Equity Method Investees’ Other Comprehensive Income (Loss)
Changes in AOCI balances by component (after-tax)
BALANCE, beginning of year	(23,672)	(32,614)
Other comprehensive income before reclassifications	(2,464)	4,476
Amounts reclassified from AOCI	142	505
TOTAL OTHER COMPREHENSIVE INCOME, NET OF TAX	(2,322)	4,981
BALANCE, end of year	(25,994)	(27,633)
Defined Benefit Pension and Postretirement Plans
Changes in AOCI balances by component (after-tax)
BALANCE, beginning of year	(204,649)	(152,058)
Other comprehensive income before reclassifications	0	0
Amounts reclassified from AOCI	2,064	1,176
TOTAL OTHER COMPREHENSIVE INCOME, NET OF TAX	2,064	1,176
BALANCE, end of year	(202,585)	(150,882)
Unrealized Gain (Loss) on Derivative Contracts
Changes in AOCI balances by component (after-tax)
BALANCE, beginning of year	(5,410)	(5,684)
Other comprehensive income before reclassifications	2,696	(3,761)
Amounts reclassified from AOCI	761	159
TOTAL OTHER COMPREHENSIVE INCOME, NET OF TAX	3,457	(3,602)
BALANCE, end of year	(1,953)	(9,286)
Unrealized Gain (Loss) on Available-for- Sale Securities
Changes in AOCI balances by component (after-tax)
BALANCE, beginning of year		(709)
Other comprehensive income before reclassifications		0
Amounts reclassified from AOCI		709
TOTAL OTHER COMPREHENSIVE INCOME, NET OF TAX		709
BALANCE, end of year		0
Accumulated Other Comprehensive Income (Loss), Net Attributable to Noncontrolling Interests
Changes in AOCI balances by component (after-tax)
BALANCE, beginning of year	(3,701)	(1,462)
BALANCE, end of year	(3,216)	(1,122)
Foreign Currency Translation
Changes in AOCI balances by component (after-tax)
BALANCE, beginning of year	(3,701)	(1,462)
Other comprehensive income before reclassifications	485	340
Amounts reclassified from AOCI	0	0
TOTAL OTHER COMPREHENSIVE INCOME, NET OF TAX	485	340
BALANCE, end of year	(3,216)	(1,122)
Ownership Share of Equity Method Investees’ Other Comprehensive Income (Loss)
Changes in AOCI balances by component (after-tax)
BALANCE, beginning of year	0	0
Other comprehensive income before reclassifications	0	0
Amounts reclassified from AOCI	0	0
TOTAL OTHER COMPREHENSIVE INCOME, NET OF TAX	0	0
BALANCE, end of year	0	0
Defined Benefit Pension and Postretirement Plans
Changes in AOCI balances by component (after-tax)
BALANCE, beginning of year	0	0
Other comprehensive income before reclassifications	0	0
Amounts reclassified from AOCI	0	0
TOTAL OTHER COMPREHENSIVE INCOME, NET OF TAX	0	0
BALANCE, end of year	0	0
Unrealized Gain (Loss) on Derivative Contracts
Changes in AOCI balances by component (after-tax)
BALANCE, beginning of year	0	0
Other comprehensive income before reclassifications	0	0
Amounts reclassified from AOCI	0	0
TOTAL OTHER COMPREHENSIVE INCOME, NET OF TAX	0	0
BALANCE, end of year	0	0
Unrealized Gain (Loss) on Available-for- Sale Securities
Changes in AOCI balances by component (after-tax)
BALANCE, beginning of year		0
Other comprehensive income before reclassifications		0
Amounts reclassified from AOCI		0
TOTAL OTHER COMPREHENSIVE INCOME, NET OF TAX		0
BALANCE, end of year		0
Noncontrolling Interests
Changes in AOCI balances by component (after-tax)
BALANCE, beginning of year	154,869	150,089
Other comprehensive income before reclassifications	485	340
Amounts reclassified from AOCI	0	0
TOTAL OTHER COMPREHENSIVE INCOME, NET OF TAX	485	340
BALANCE, end of year	$ 163,612	$ 132,996