Annual report pursuant to Section 13 and 15(d)

Income Taxes - Unrecognized Tax Benefits (Details)

v3.8.0.1
Income Taxes - Unrecognized Tax Benefits (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Income Tax Disclosure [Abstract]      
Income tax interest and penalties $ 6,500 $ 6,100 $ 1,400
Reconciliation of Unrecognized Tax Benefits [Roll Forward]      
Balance at beginning of year 11,048 4,637 4,237
Additions from business combinations 0 3,492 0
Increase to prior year positions 0 (34) 0
Reversal of prior tax positions (3,045) (147) 0
Additions based on tax positions related to current year 725 3,100 400
Balance at end of year $ 8,728 $ 11,048 $ 4,637