Stock-Based Compensation Stock-Based Compensation - Performance Vesting Stock Options (Details) shares in Thousands	Mar. 31, 2019 shares
2019/2020 | Awards Vesting in 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of exercisable options (in shares)	104
2019/2020 | Awards Vesting in 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of exercisable options (in shares)	104
2018/2019 | Awards Vesting in 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of exercisable options (in shares)	0
2018/2019 | Awards Vesting in 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of exercisable options (in shares)	0
2017/2018 | Awards Vesting in 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of exercisable options (in shares)	0
2017/2018 | Awards Vesting in 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of exercisable options (in shares)	0
2016/2017 | Awards Vesting in 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of exercisable options (in shares)	173