7. Stockholders' Equity Treasury Shares (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Authorized Amount	$ 18.0
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 3.3
Treasury Class-A [Member]
Equity, Class of Treasury Stock [Line Items]
Treasury Stock, Shares	122	122
Treasury Class B [Member]
Equity, Class of Treasury Stock [Line Items]
Treasury Stock, Shares	917	917