XML 108 R93.htm IDEA: XBRL DOCUMENT v3.3.1.900
Employee Benefit Plans - Additional Information (Detail) - USD ($)
$ in Thousands
 8 Months Ended 12 Months Ended
Dec. 31, 2014
Dec. 31, 2015
Apr. 30, 2014
Apr. 30, 2013
Employee Stock Purchase Plan [Line Items]        
Employer contributions $ 497 $ 1,033 $ 784 $ 645
Defined contribution plan, description   We provide an employer matching contribution equal to fifty cents for every dollar an employee invests in the 401(k) Plan up to our maximum match of one thousand dollars per employee per calendar year, subject to revision.    
Employer contributions vesting period   3 years    
Class A Common Stock [Member]        
Employee Stock Purchase Plan [Line Items]        
Discount rate   15.00%    
Common stock, authorized shares   1,200,000    
Stock issued under stock purchase plan 79,000 80,000 70,000 76,000
Stock available for distribution under stock purchase plan   255,000