v3.8.0.1
Income Taxes - Summary of Income Tax Expenses (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Current:      
Federal $ 24,421 $ 17,139 $ 7,918
State 1,411 1,098 546
Deferred:      
Federal (13,289) (905) 16,486
State 316 (357) (171)
Total Income Tax Expense $ 12,859 $ 16,975 $ 24,779