Options and Awards Restricted Awards Granted (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands |
12 Months Ended | ||
---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
Restricted awards granted [Line Items] | |||
Restricted Awards Grant Date Fair Value Range, Minimum | $ 18.47 | $ 18.79 | $ 21.00 |
Restricted Awards Grant Date Fair Value Range, Maximum | $ 22.90 | $ 23.23 | $ 26.55 |
Share-based Compensation, Restricted Awards, Exercise Price | $ 0 | ||
Issuance of restricted stock to employees (in shares) | 173 | 299 | 323 |
Award Vesting Period | 5 years | ||
Director [Member] | |||
Restricted awards granted [Line Items] | |||
Restricted Awards Grant Date Fair Value Range, Minimum | $ 18.47 | ||
Restricted Awards Grant Date Fair Value Range, Maximum | $ 21.96 | ||
Options Granted to Non-employee Directors | 30 |