Accumulated Other Comprehensive Income (Loss) (AOCI balances) (Details 2) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
As of	$ 2,916,782	$ 2,915,145
Other Comprehensive Income, Net of Tax	8,290	10,812
As of	2,999,536	2,884,388
AOCI Including Portion Attributable to Noncontrolling Interest [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
As of	203,829
Other comprehensive (loss) income before reclassifications	9,728
Net amount reclassified from accumulated other comprehensive income (loss)	(1,438)
Other Comprehensive Income, Net of Tax	8,290
As of	212,119
Cumulative Foreign Currency Translation Adjustment [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
As of	(29,270)
Other comprehensive (loss) income before reclassifications	10,033
Net amount reclassified from accumulated other comprehensive income (loss)	0
Other Comprehensive Income, Net of Tax	10,033	11,564
As of	(19,237)
Unrealized Gain on Pensions and Other Postretirement Plans [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
As of	232,836
Other comprehensive (loss) income before reclassifications	0
Net amount reclassified from accumulated other comprehensive income (loss)	(1,384)	(943)
Other Comprehensive Income, Net of Tax	(1,384)	(943)
As of	231,452
Cash Flow Hedges [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
As of	263
Other comprehensive (loss) income before reclassifications	(305)
Net amount reclassified from accumulated other comprehensive income (loss)	(54)
Other Comprehensive Income, Net of Tax	(359)	$ 191
As of	$ (96)