Income Taxes (Details) - USD ($)	9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2012	Dec. 31, 2015
Unrecognized Tax Benefits [Abstract]
Unrecognized tax benefit — Permanent tax positions	$ 2,700,000			$ 2,400,000
Unrecognized tax benefit — Temporary tax positions	16,200,000			15,000,000
Total unrecognized tax benefit	18,900,000			17,400,000
NOL and tax credit carryforwards	(5,400,000)			(4,300,000)
Upper bound of decrease in unrecognized tax benefit that is reasonably possible	11,000,000
Amounts accrued for penalties related to unrecognized tax benefits	0			$ 0
Internal Revenue Service (IRS)
Tax Audits [Abstract]
Year(s) under examination		2012 and 2013	2010 and 2011
Year of carryback claim under examination			2009
Potential Tax Adjustments	$ 14,000,000
Earliest year subject to examination	2009
State Jurisdiction (Colorado)
Tax Audits [Abstract]
Earliest year subject to examination	2009