Income Taxes (Details) (USD $)			3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended
	Jun. 30, 2013	Dec. 31, 2012	Sep. 30, 2012 Internal Revenue Service (IRS)	Jun. 30, 2013 Internal Revenue Service (IRS)	Dec. 31, 2012 State Jurisdiction (Colorado)	Jun. 30, 2013 State Jurisdiction (Colorado)
Tax Audits [Abstract]
Year(s) no longer subject to audit as statute of limitations has expired				2008
Earliest year subject to examination				2009		2006
Year(s) under examination			2010 and 2011		2006 through 2009
Unrecognized Tax Benefits [Abstract]
Unrecognized tax benefit — Permanent tax positions	$ 1,300,000	$ 1,300,000
Unrecognized tax benefit — Temporary tax positions	9,000,000	8,300,000
Total unrecognized tax benefit	10,300,000	9,600,000
NOL and tax credit carryforwards	(6,800,000)	(5,300,000)
Upper bound of decrease in unrecognized tax benefit that is reasonably possible	(9,000,000)
Amounts accrued for penalties related to unrecognized tax benefits	$ 0	$ 0