Accumulated Other Comprehensive Income (Loss) (AOCI balances) (Details 2) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income, beginning balance			$ 2,452,941
Other Comprehensive Income (Loss), Net of Tax	$ 17,139	$ (10,770)	35,421	$ (7,535)
Accumulated Other Comprehensive Income, ending balance	2,536,372		2,536,372
AOCI Including Portion Attributable to Noncontrolling Interest [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income, beginning balance			236,486
Other comprehensive (loss) income before reclassifications			37,254
Net amount reclassified from accumulated other comprehensive income			(1,833)
Other Comprehensive Income (Loss), Net of Tax			35,421
Accumulated Other Comprehensive Income, ending balance	271,907		271,907
Cumulative Foreign Currency Translation Adjustment [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income, beginning balance			(26,998)
Other comprehensive (loss) income before reclassifications	9,638	(5,121)	23,306	(1,276)
Net amount reclassified from accumulated other comprehensive income			0
Other Comprehensive Income (Loss), Net of Tax			23,306
Accumulated Other Comprehensive Income, ending balance	(3,692)		(3,692)
Unrealized Gain on Available-for-Sale Securities [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income, beginning balance			92,931
Other comprehensive (loss) income before reclassifications	8,385	(3,184)	14,120	(2,978)
Net amount reclassified from accumulated other comprehensive income	0	(2,701)	0	(3,754)
Other Comprehensive Income (Loss), Net of Tax	8,385	(5,885)	14,120	(6,732)
Accumulated Other Comprehensive Income, ending balance	107,051		107,051
Unrealized Gain on Pensions and Other Postretirement Plans [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income, beginning balance			170,830
Other comprehensive (loss) income before reclassifications			0
Net amount reclassified from accumulated other comprehensive income	(869)	236	(1,891)	473
Other Comprehensive Income (Loss), Net of Tax	(869)	236	(1,891)	473
Accumulated Other Comprehensive Income, ending balance	168,939		168,939
Cash Flow Hedge [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income, beginning balance			(277)
Other comprehensive (loss) income before reclassifications			(172)
Net amount reclassified from accumulated other comprehensive income			58
Other Comprehensive Income (Loss), Net of Tax	(15)	$ 0	(114)	$ 0
Accumulated Other Comprehensive Income, ending balance	$ (391)		$ (391)