Income Taxes (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Income Taxes [Line Items]
Net operating loss carryforwards	$ 420,800,000
Net capital loss carryforwards	1,400,000
Deferred tax assets related to capital loss-carryforwards	500,000
Deferred tax asset related to loss carryforwards	32,276,000	28,914,000
Net operating loss carryforwards, valuation allowance	15,800,000
Net capital loss carryforwards, valuation allowance	500,000
Unrecognized tax benefits affecting effective tax rate	35,500,000
Interest and penalties associated with unrecognized tax benefits (Operations)	3,000,000
Interest and penalties associated with unrecognized tax benefits (Balance Sheet)	20,600,000
Operating Loss Carryforward Expiring 2031 [Member]
Income Taxes [Line Items]
Net operating loss carryforward, expiration dates	2031
Wisconsin Research And Development Credit [Member]
Income Taxes [Line Items]
Wisconsin research and development credit carryforwards	15,000,000
Capital Loss Carryforward Expiring Between 2012 And 2013 [Member]
Income Taxes [Line Items]
Deferred tax asset related to loss carryforwards	$ 31,800,000