Accumulated Other Comprehensive Income (Loss) (AOCI balances) (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income, beginning balance	$ 699,494
Other comprehensive income (loss) before reclassifications	17,364
Net amount reclassified from accumulated other comprehensive income	(3,773)
Other Comprehensive Income, Net of Tax	13,591	23,988
Accumulated Other Comprehensive Income, ending balance	713,085
Foreign Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income, beginning balance	25,013
Other comprehensive income (loss) before reclassifications	746
Net amount reclassified from accumulated other comprehensive income	0
Other Comprehensive Income, Net of Tax	746
Accumulated Other Comprehensive Income, ending balance	25,759
Unrealized Gain on Available-for-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income, beginning balance	173,663
Other comprehensive income (loss) before reclassifications	16,642
Net amount reclassified from accumulated other comprehensive income	471
Other Comprehensive Income, Net of Tax	17,113
Accumulated Other Comprehensive Income, ending balance	190,776
Unrealized Gain on Pensions and Other Postretirement Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income, beginning balance	501,446
Other comprehensive income (loss) before reclassifications	0
Net amount reclassified from accumulated other comprehensive income	(4,371)
Other Comprehensive Income, Net of Tax	(4,371)
Accumulated Other Comprehensive Income, ending balance	497,075
Cash Flow Hedge [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income, beginning balance	(628)
Other comprehensive income (loss) before reclassifications	(24)
Net amount reclassified from accumulated other comprehensive income	127
Other Comprehensive Income, Net of Tax	103
Accumulated Other Comprehensive Income, ending balance	$ (525)