Income Taxes (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Taxes [Abstract]
Net operating loss carryforwards, use limit	$ 2,100,000
Federal net operating loss carryforwards	31,000,000
State net operating loss carryforwards	141,500,000
Alternative minimum tax credit	900,000
Federal research and development credits	1,000,000
Unrecognized tax benefits	19,413,000	19,362,000	19,721,000	23,965,000
Unrecognized tax benefits that would impact effective tax rate if recognized and realized	19,100,000
Extension of bonus depreciation and research and development credit (as a percent)	50.00%
Lapse in statute of limitations	$ 11,000,000