Income Taxes (Recognized Income Tax Expense) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Federal:
Current	$ (2,877)	$ 1,487	$ 5,084
Deferred	45,024	43,187	46,864
Total federal income tax	42,147	44,674	51,948
State:
Current	1,854	1,931	2,936
Deferred	(414)	697	(924)
Total state income tax	1,440	2,628	2,012
Generation & Amortization of accumulated investment tax credit	68	(323)	(252)
Total income tax expense	$ 43,655	$ 46,979	$ 53,708