Accounting Changes and Error Corrections Accounting Changes and Error Corrections (Details Textual) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Depreciation, Depletion and Amortization	$ 65,331	$ 67,274	$ 201,072	$ 187,503
Net Income	2,474	7,359	14,743	22,946	(2,442)
Provision for Income Taxes	3,001	5,625	14,200	15,235
Restatement Adjustment [Member]
Depreciation, Depletion and Amortization		326		977
Net Income		(1,527)		129
Provision for Income Taxes		(867)		73
Ceiling Test Error Correction [Member] | Restatement Adjustment [Member]
Depreciation, Depletion and Amortization		300		1,000
Net Income		200		600
Provision for Income Taxes		$ 100		$ 400