Annual report pursuant to Section 13 and 15(d)

Business and Summary of Significant Accounting Principles (Recently Issued and Recently Adopted Accounting Pronouncements) (Details)

v3.8.0.1
Business and Summary of Significant Accounting Principles (Recently Issued and Recently Adopted Accounting Pronouncements) (Details) - USD ($)
$ in Thousands
Jan. 01, 2018
Dec. 31, 2017
Dec. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]      
Retained earnings   $ (12,296) $ 17,068
Cumulative effect of ASU 2016-09 adoption     7,095
Retained Earnings (Deficit)      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]      
Cumulative effect of ASU 2016-09 adoption     $ 7,077
ASU 2014-09 | Subsequent Event      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]      
Retained earnings $ 33,300