XML 100 R84.htm IDEA: XBRL DOCUMENT v3.8.0.1
Employee plans - Summary of Stock Option Activity (Details)
$ / shares in Units, $ in Millions
 12 Months Ended
Dec. 31, 2017
USD ($)
$ / shares
shares
Shares  
Outstanding at beginning of period (in shares) | shares 2,099,000
Granted (in shares) | shares 0
Exercised (in shares) | shares (1,000)
Forfeited and expired (in shares) | shares (340,000)
Outstanding at end of period (in shares) | shares 1,758,000
Expected to vest at end of period (in shares) | shares 198,000
Exercisable at end of period (in shares) | shares 1,558,000
Weighted- Average Exercise Price  
Outstanding at beginning of period (in dollars per share) | $ / shares $ 25.41
Granted (in dollars per share) | $ / shares 0.00
Exercised (in dollars per share) | $ / shares 10.65
Forfeited and expired (in dollars per share) | $ / shares 20.59
Outstanding at end of period (in dollars per share) | $ / shares 26.35
Expected to vest at end of period (in dollars per share) | $ / shares 23.20
Exercisable at end of period (in dollars per share) | $ / shares $ 26.76
Weighted- Average Remaining Contractual Term (years)  
Outstanding at end of period 1 year 6 months 21 days
Expected to vest at end of period 3 years 5 months 1 day
Exercisable at end of period 1 year 3 months 29 days
Aggregate Intrinsic Value  
Outstanding at end of period | $ $ 0.0
Expected to vest at end of period | $ 0.0
Exercisable at end of period | $ $ 0.0