Consolidated Statements of Shareholders' Equity (Parenthetical) - $ / shares |
12 Months Ended | ||
|---|---|---|---|
May 31, 2019 |
May 31, 2018 |
May 31, 2017 |
|
| Statement of Stockholders' Equity [Abstract] | |||
| Dividends declared per common share (in dollars per share) | $ 0.86 | $ 0.78 | $ 0.70 |
| Dividends declared per preferred share (in dollars per share) | $ 0.10 | $ 0.10 | $ 0.10 |