Basis and Summary of Significant Accounting Policies - Calculation of Dilutive Stock Awards (Details) - shares shares in Thousands |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2019 |
Jun. 30, 2018 |
Jun. 30, 2019 |
Jun. 30, 2018 |
|
| Accounting Policies [Abstract] | ||||
| Weighted Average Shares Outstanding (in shares) | 67,687 | 69,645 | 67,492 | 69,875 |
| Dilutive Effect of Share-Based Awards (in shares) | 1,106 | 1,192 | 1,292 | 1,553 |
| Weighted Average Shares Outstanding Assuming Dilution (in shares) | 68,793 | 70,837 | 68,784 | 71,428 |
| Anti-dilutive securities excluded from the computation of earnings per share assuming dilution (in shares) | 522 | 493 | 482 | 340 |