Income Taxes - (Details Textual) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Non-cash tax benefit due to Tax Cuts and Jobs Act	$ 13,712,000
Re-measurement of deferred tax assets due to Tax Cuts and Jobs Act	123,289,000
Release of valuation allowances due to Tax Cuts and Jobs Act	137,001,000
Impairment of goodwill		$ 0	$ 0	$ 175,028,000
Impairment of goodwill, not tax deductible				91,961,000
Tax impact related to the non-deductible portion of the goodwill impairment change				32,186,000
Goodwill impairment tax impact		0	(2,876,000)	35,062,000
Deferred tax asset reflecting federal and state net operating losses	249,371,000	249,371,000	346,768,000
Federal net operating losses	934,137,000	$ 934,137,000
Expiration date for federal net operating losses		2028
Unrecognized tax benefits that would affect the effective tax rate	$ 0	$ 0	$ 0	$ 0
Period for unrecognized tax benefits to increase or decrease		12 months
Interest and penalties related to unrecognized tax benefits		$ 0