Reconciliation of Effective Federal Tax Rates with Statutory Federal Income Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
U.S. federal statutory rate	34.00%	34.00%	34.00%
State income taxes	(0.30%)	(0.60%)	4.90%
Foreign income taxes	(0.40%)	(0.40%)	0.00%
Deferred tax valuation allowance	(24.60%)	(26.50%)	(131.30%)
Fair value adjustments	0.00%	(1.20%)	14.70%
Revisions to prior years	(0.10%)	19.10%	171.40%
Goodwill impairment	(9.50%)	0.00%	0.00%
Other permanent items	1.40%	(2.10%)	(0.10%)
Other	0.00%	0.00%	4.70%
Effective tax rate	0.50%	22.30%	98.30%