Quarterly report pursuant to Section 13 or 15(d)

Basis of Presentation - Narrative (Details)

v3.8.0.1
Basis of Presentation - Narrative (Details) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Sep. 30, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]      
Reduction to income tax expense     $ 1,234
Diluted (in dollars per share) $ 1.10 $ 0.32  
Accounting Standards Update 2016-09      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]      
Diluted (in dollars per share)     $ 0.04