Accumulated Other Comprehensive Income (Loss) (AOCI balances) (Details 2) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income, beginning balance			$ 2,490,698
Other Comprehensive Income (Loss), Net of Tax	$ 7,205	$ (4,713)	(330)	$ (23,330)
Accumulated Other Comprehensive Income, ending balance	2,508,799		2,508,799
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			314,680
Other comprehensive (loss) income before reclassifications			2,716
Net amount reclassified from accumulated other comprehensive income			(3,046)
Other Comprehensive Income (Loss), Net of Tax			(330)
Accumulated Other Comprehensive Income, ending balance	314,350		314,350
Cumulative Foreign Currency Translation Adjustment [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income, beginning balance			(4,849)
Other comprehensive (loss) income before reclassifications	(353)	(10,548)	(1,629)	(17,387)
Net amount reclassified from accumulated other comprehensive income	0	6,026	0	5,501
Other Comprehensive Income (Loss), Net of Tax	(353)	(4,522)	(1,629)	(11,886)
Accumulated Other Comprehensive Income, ending balance	(6,478)		(6,478)
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			58,500
Other comprehensive (loss) income before reclassifications	7,292	2,301	4,314	(9,898)
Net amount reclassified from accumulated other comprehensive income			(3,754)	0
Other Comprehensive Income (Loss), Net of Tax			560	(9,898)
Accumulated Other Comprehensive Income, ending balance	59,060		59,060
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			261,029
Other comprehensive (loss) income before reclassifications			0
Net amount reclassified from accumulated other comprehensive income	237	(3,334)	710	(2,496)
Other Comprehensive Income (Loss), Net of Tax	237	(2,492)	710	(1,654)
Accumulated Other Comprehensive Income, ending balance	261,739		261,739
Cash Flow Hedge [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income, beginning balance			0
Other comprehensive (loss) income before reclassifications			31
Net amount reclassified from accumulated other comprehensive income			(2)
Other Comprehensive Income (Loss), Net of Tax	29	$ 0	29	$ 108
Accumulated Other Comprehensive Income, ending balance	$ 29		$ 29