Annual report pursuant to Section 13 and 15(d)

Shareholders' Equity - Declared Quarterly Cash Dividends on Common Stock (Details)

v3.8.0.1
Shareholders' Equity - Declared Quarterly Cash Dividends on Common Stock (Details) - $ / shares
3 Months Ended 12 Months Ended
Jan. 31, 2018
Oct. 25, 2017
Jul. 26, 2017
Apr. 26, 2017
Jan. 26, 2017
Mar. 31, 2018
Dec. 31, 2017
Subsequent Event [Line Items]              
Dividends per share (in dollars per share)   $ 0.12 $ 0.12 $ 0.075 $ 0.075   $ 0.39000000
Subsequent Event              
Subsequent Event [Line Items]              
Dividends per share (in dollars per share) $ 0.120         $ 0.12