Accumulated Other Comprehensive Income (Schedule of Accumulated Other Comprehensive Income (Loss)) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014
Accumulated Other Comprenhensive Income (Loss) [Roll Forward]
Balance at December 31, 2013	$ 37,692
Unrealized gains (losses)	(3,083)
Amounts reclassified from AOCI	(3,103)
Balance at September 30, 2014	31,506
Derivative Instruments [Member]
Accumulated Other Comprenhensive Income (Loss) [Roll Forward]
Balance at December 31, 2013	565
Unrealized gains (losses)	1,692
Amounts reclassified from AOCI	(861)
Balance at September 30, 2014	1,396
Pension, Postretirement and Other Postemployment Benefits [Member]
Accumulated Other Comprenhensive Income (Loss) [Roll Forward]
Balance at December 31, 2013	31,112
Unrealized gains (losses)	0
Amounts reclassified from AOCI	(3,409)
Balance at September 30, 2014	27,703
Available-for-Sale Securities [Member]
Accumulated Other Comprenhensive Income (Loss) [Roll Forward]
Balance at December 31, 2013	6,015
Unrealized gains (losses)	(4,775)
Amounts reclassified from AOCI	1,167
Balance at September 30, 2014	$ 2,407