Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity (Narrative) (Details)

v3.7.0.1
Stockholders' Equity (Narrative) (Details)
6 Months Ended
Jun. 30, 2017
$ / shares
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Outstanding options that are exercisable (shares) 1,400,000
Outstanding options that are exercisable, weighted average exercise price (in USD per share) | $ / shares $ 35.12
Employee Stock Purchase Plan  
Employee Stock Purchase Plan  
Share purchase price as percent of market price (percent) 85.00%
Shares issued in period (shares) 2,232
Shares available for future purchases (shares) 68,065