Accumulated Other Comprehensive Income (Schedule of Accumulated Other Comprehensive Income (Loss)) (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2015 USD ($)
Accumulated Other Comprenhensive Income (Loss) [Roll Forward]
Balance at December 31, 2014	$ 3,241
Unrealized gains (losses)	518
Amounts reclassified from AOCI	2,208
Balance at September 30, 2015	5,967
Derivative Instruments [Member]
Accumulated Other Comprenhensive Income (Loss) [Roll Forward]
Balance at December 31, 2014	2,550
Unrealized gains (losses)	3,919
Amounts reclassified from AOCI	(4,354)
Balance at September 30, 2015	2,115
Pension, Postretirement and Other Postemployment Benefits [Member]
Accumulated Other Comprenhensive Income (Loss) [Roll Forward]
Balance at December 31, 2014	2,860
Unrealized gains (losses)	0
Amounts reclassified from AOCI	3,168
Balance at September 30, 2015	6,028
Available-for-Sale Securities [Member]
Accumulated Other Comprenhensive Income (Loss) [Roll Forward]
Balance at December 31, 2014	(2,169)
Unrealized gains (losses)	(3,401)
Amounts reclassified from AOCI	3,394
Balance at September 30, 2015	$ (2,176)