Income Taxes (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Income Taxes [Line Items]
U.S. federal statutory corporate pretax rate	35.00%
State NOL carryforwards, valuation allowance	$ 1.2
Ownership percentage change	5.00%
Change in beneficial ownership, percentage	50.00%
Annual limitation on net operating loss carryforwards	12.6
Pre-change in net operating loss	9.8
Stock-based compensation deductions not reflected in deferred tax assets	29.2
Recognized deferred tax assets associated with stock based compensation tax deductions	10.2
Minimum [Member]
Income Taxes [Line Items]
Net operating loss carryforward expiration dates	2019
Maximum [Member]
Income Taxes [Line Items]
Net operating loss carryforward expiration dates	2032
United States Of America [Member]
Income Taxes [Line Items]
Operating loss carry forwards subject to expiration	$ 176.9