Quarterly report pursuant to Section 13 or 15(d)

Shareholders' Equity Shareholders' Equity (Details)

v3.8.0.1
Shareholders' Equity Shareholders' Equity (Details) - USD ($)
$ / shares in Units, $ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2017
Jun. 30, 2017
Mar. 31, 2017
Sep. 30, 2016
Sep. 30, 2017
Sep. 30, 2016
Stock Repurchased and Retired During Period, Shares 9,305       91,921  
Stock Repurchased and Retired During Period, Value $ 0.9       $ 8.0  
Stock Repurchase Program, Remaining Authorized Repurchase Amount $ 192.0       $ 192.0  
Dividends [Abstract]            
Dividends declared per share $ 0.10 $ 0.10 $ 0.10 $ 0.00 $ 0.30 $ 0.00
2016 Share Repurchase Program [Member]            
Stock Repurchase Program, Authorized Amount $ 250.0       $ 250.0  
2014 Share Repurchase Program [Member]            
Stock Repurchase Program, Authorized Amount $ 200.0       $ 200.0