Earnings per common share (Details) - $ / shares shares in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Earnings Per Share [Abstract]
Weighted average common shares outstanding - basic	196,401	195,304
Effect of dilutive performance share awards and restricted stock units	13	678
Weighted average common shares outstanding - diluted	196,414	195,982
Shares excluded from the calculation of diluted earnings per share	64	0
Dividends declared per common share	$ 0.2025	$ 0.1975

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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- Definition

Aggregate dividends declared during the period for each share of common stock outstanding.

+ References

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-Publisher FASB
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- References

No definition available.

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- Definition

The sum of dilutive potential common shares or units used in the calculation of the diluted per-share or per-unit computation.

+ References

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- Definition

The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

+ References

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-Topic 260
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-Section 50
-Paragraph 1
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- Definition

Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

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