Income Taxes - Schedule of Common Stock Dividends Characterized for Tax (Details) - Income Tax - $ / shares |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Dividends Per Share [Line Items] | |||
| Common stock dividends paid (in dollars per share) | $ 0.72 | $ 0.7 | $ 0.68 |
| Common Shares | |||
| Dividends Per Share [Line Items] | |||
| Ordinary income (in dollars per share) | 0.49 | 0.52 | 0.42 |
| Return of capital (in dollars per share) | 0.16 | 0.15 | 0.26 |
| Capital gain (in dollars per share) | $ 0.07 | $ 0.03 | $ 0 |