Shareholders' equity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Dividends [Abstract]
Dividends declared and paid per common share (in dollars per share)	$ 0.09	$ 0.09
Payment of dividend on common stock	$ 668	$ 673
Dividends, date paid	Mar. 15, 2019
Dividends, date of record	Feb. 20, 2019
Stock repurchase program [Abstract]
Common stock repurchased (in shares)	0	122,780

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- Definition

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

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Date the declared dividend will be paid, in CCYY-MM-DD format.

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Date the holder must own the stock to be entitled to the dividend, in CCYY-MM-DD format.

+ References

No definition available.

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Amount of cash outflow in the form of ordinary dividends to common shareholders of the parent entity.

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- Definition

Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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