Provision (Benefit) for Income Taxes (Details 3) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Deferred tax assets:
Federal net operating losses ("NOLs")	$ 117,984	$ 93,600
NOLs for excess stock-based compensation	(9,615)	(9,676)
State NOL carryovers	14,626	13,686
Alternative minimum tax credits	2,092	2,092
Deferred Tax Assets, Other Loss Carryforwards	1,295	1,378
Unrealized share-based compensation	9,957	9,096
Valuation allowance	(6,703)	(6,318)
Other	6,050	5,909
Total deferred tax assets	135,686	109,767
Deferred tax liabilities:
Deferred Tax Liabilities, Property, Plant and Equipment	(347,178)	(324,031)
Other	(918)	(3,300)
Total deferred tax liabilities	(348,096)	(327,331)
Net deferred tax liabilities	(212,410)	(217,564)
Net current deferred tax assets	4,974	5,679
Net non-current deferred tax liabilities	$ (217,384)	$ (223,243)