Stockholders' Equity Stockholders' Equity (Stock-Based Compensation Plans) (Details) shares in Thousands	Sep. 30, 2017 shares
Class of Stock [Line Items]
Shares Reserved (in shares)	1,571
Shares Available to Issue (in shares)	1,541
Options Outstanding (in shares)	1,945
Performance Awards Outstanding (in shares)	328
Amended And Restated 2006 Plan [Member]
Class of Stock [Line Items]
Shares Reserved (in shares)	0
Shares Available to Issue (in shares)	0
Options Outstanding (in shares)	1,929
Performance Awards Outstanding (in shares)	319
2017 Plan [Member]
Class of Stock [Line Items]
Shares Reserved (in shares)	1,571
Shares Available to Issue (in shares)	1,541
Options Outstanding (in shares)	16
Performance Awards Outstanding (in shares)	9