XML 89 R69.htm IDEA: XBRL DOCUMENT v3.8.0.1
Income Taxes - Additional Information (Detail) - USD ($)
 4 Months Ended 8 Months Ended 12 Months Ended 36 Months Ended
Apr. 30, 2018
Dec. 31, 2017
Apr. 30, 2018
Apr. 30, 2017
Apr. 30, 2016
Apr. 30, 2018
Apr. 30, 2015
Schedule Of Income Taxes [Line Items]              
U.S. corporate federal statutory income tax rate 21.00% 35.00% 30.40% 35.00% 35.00%    
One-time tax on accumulated foreign earnings (Transition Tax), applicable rate on cash and other specified assets 15.50%            
One-time tax on accumulated foreign earnings (Transition Tax), applicable rate on other residual earnings 8.00%            
Provisional tax charge for the Transition Tax     $ 18,400,000        
Provisional tax (benefit) from remeasurement of U.S. federal     (5,900,000)        
Undistributed earnings of foreign subsidiaries $ 492,300,000   492,300,000     $ 492,300,000  
Unrecognized tax benefits liability 3,674,000   3,674,000 $ 2,478,000 $ 2,095,000 3,674,000 $ 2,423,000
Unrecognized tax benefits, reductions resulting from resolution (3,100,000)   (3,100,000)     (3,100,000)  
Unrecognized tax benefits, interest on income taxes accrued 300,000   300,000 0   300,000  
Unrecognized tax benefits, income tax penalties accrued 0   0 $ 0   0  
Unrecognized tax benefits, interest           300,000  
Internal Revenue Service (IRS)              
Schedule Of Income Taxes [Line Items]              
Net operating loss carryforward 3,200,000   $ 3,200,000     3,200,000  
Net operating loss carryforward, beginning expiration     2028        
State and Local Jurisdiction              
Schedule Of Income Taxes [Line Items]              
Net operating loss carryforward 61,200,000   $ 61,200,000     61,200,000  
Net operating loss carryforward, beginning expiration     2019        
Foreign Tax Authority              
Schedule Of Income Taxes [Line Items]              
Net operating loss carryforward $ 87,800,000   $ 87,800,000     $ 87,800,000  
Net operating loss carryforward, beginning expiration     2019