Accumulated Other Comprehensive Income (Loss) (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reclassifications out of other comprehensive income (loss)
Amortization of (gain) loss									$ 115,974	$ 114,875	$ 108,508
Income Tax Expense									5,910	8,782	(91,362)
Net income	(1,976)	(1,516)	(2,239)	(2,368)	(2,628)	(2,061)	(3,951)	(1,848)	(8,099)	(10,488)	(109,982)
Reclassifications out of accumulated other comprehensive income (loss)
Reclassifications out of other comprehensive income (loss)
Amortization of (gain) loss									195	984	547
Retirement plans
Reclassifications out of other comprehensive income (loss)
Income Tax Expense									74	374
Net income									$ 121	$ 610	$ 547