XML 60 R50.htm IDEA: XBRL DOCUMENT v3.8.0.1
Income Taxes - Components of Income Taxes and Comprehensive Provision for Income Taxes Allocation (Parenthetical) (Detail)
3 Months Ended
Mar. 31, 2018
Dec. 31, 2017
Mar. 31, 2017
Income Tax Disclosure [Abstract]      
U.S. Federal statutory income tax rate 21.00% 35.00% 35.00%