Accumulated Other Comprehensive Income (Schedule of Accumulated Other Comprehensive Income (Loss)) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014
Accumulated Other Comprenhensive Income (Loss) [Roll Forward]
Balance at December 31, 2013	$ 37,692
Unrealized gains (losses)	(2,358)
Amounts reclassified from AOCI	(1,849)
Balance at June 30, 2014	33,485
Derivative Instruments [Member]
Accumulated Other Comprenhensive Income (Loss) [Roll Forward]
Balance at December 31, 2013	565
Unrealized gains (losses)	788
Amounts reclassified from AOCI	(290)
Balance at June 30, 2014	1,063
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	(2,634)
Balance at June 30, 2014	28,478
Available-for-Sale Securities [Member]
Accumulated Other Comprenhensive Income (Loss) [Roll Forward]
Balance at December 31, 2013	6,015
Unrealized gains (losses)	(3,146)
Amounts reclassified from AOCI	1,075
Balance at June 30, 2014	$ 3,944