Annual report pursuant to Section 13 and 15(d)

Income Taxes - Additional Information (Detail)

v3.8.0.1
Income Taxes - Additional Information (Detail) - USD ($)
$ in Thousands
 3 Months Ended 12 Months Ended
Dec. 31, 2017
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Income Taxes [Line Items]          
Provision for income taxes (benefit) expense related to remeasurement of net deferred tax liability $ (28,400)   $ (28,400)    
U.S. statutory federal income tax rate     35.00% 35.00% 35.00%
Net long-term deferred tax asset 2,900   $ 2,900 $ 2,400  
Net long-term deferred tax liability 51,619   51,619 76,447  
Gross deferred tax assets related to state net operating loss carryforwards 282,000   282,000    
Valuation allowance related to certain state net operating loss carryforward deferred tax assets 8,000   8,000    
Liabilities recorded related to unrecognized tax benefits       5,200  
Liabilities related to interest and penalties 600   600 800  
Unrecognized tax benefit that would affect income tax rate if recognized $ 4,700   $ 4,700 $ 3,300  
State and Local Jurisdiction [Member]          
Income Taxes [Line Items]          
Operating loss expiration date     Net operating loss carryforwards that will expire between 2018 and 2037    
Operating loss expiration, beginning year     2018    
Operating loss expiration, ending year     2037    
State and Local Jurisdiction [Member] | Tax Year 2017 [Member]          
Income Taxes [Line Items]          
Income tax examination year     2017    
State and Local Jurisdiction [Member] | Tax Year 2013 [Member]          
Income Taxes [Line Items]          
Income tax examination year     2013    
U.S. Federal Income Tax Authority [Member] | Internal Revenue Service [Member] | Tax Year 2014 [Member]          
Income Taxes [Line Items]          
Income tax examination year     2014    
U.S. Federal Income Tax Authority [Member] | Internal Revenue Service [Member] | Tax Year 2017 [Member]          
Income Taxes [Line Items]          
Income tax examination year     2017    
Scenario, Forecast [Member]          
Income Taxes [Line Items]          
U.S. statutory federal income tax rate   21.00%