Share-based compensation (Tables)

12 Months Ended

Dec. 31, 2018

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Outstanding Restricted Shares, Phantom Share Units, SARs and Restricted Stock Units

A summary of the Company’s outstanding restricted shares, phantom share units, SARs and restricted stock units as of and for the years ended December 31, 2018, 2017 and 2016 are presented below:

	Restricted shares					Phantom share units					Stock appreciation rights					Restricted stock units					Stock options
	Number			W.A.grant		Number			W.A. grant		Number of			W.A. grant		Number			W.A. grant		Number		W.A. grant
	of shares			date FV		of units			date FV		SARs			date FV		of units			date FV		of options		date FV
December 31, 2015		44,947		$	18.39	$	647,001		$	14.73	$	5,876,811		$	2.30	$	32,828		$	21.03	$	—	$	—
Granted		56,861			15.48		60,000			18.84		—			—		528,232			16.57		—		—
Vested		(44,947	)		18.39		—			—		—			—		(37,374	)		18.56		—		—
Exchanged		—			—		(70,000	)		19.91		—			—		—			—		—		—
Expired		—			—		—			—		(3,438,614	)		2.26		—			—		—		—
Cancelled		—			—		—			—		—			—		(299	)		20.21		—		—
December 31, 2016		56,861			15.48		637,001			14.55		2,438,197			2.29		523,387			16.71		—		—
Granted		107,270			8.97		90,000			6.85		—			—		88,293			5.93		—		—
Vested		(56,861	)		15.48		—			—		—			—		(537,216	)		16.16		—		—
Expired		—			—		—			—		(1,929,260	)		2.00		—			—		—		—
Cancelled		(12,737	)		9.53		—			—		(22,963	)		3.40		(3,280	)		9.16		—		—
December 31, 2017		94,533			8.89		727,001			13.60		485,974			3.40		71,184			7.80		—		—
Granted		664,326			7.68		30,000			6.86		—			—		109,248			9.73		500,000		7.20
Vested		(119,509	)		8.52		—			—		—			—		(83,220	)		9.87		—		—
Exchanged		—			—		(113,333	)		18.80		—			—		—			—		—		—
Expired		—			—		—			—		(485,974	)		3.40		—			—		—		—
Cancelled		(53,608	)		7.10		(76,666	)		7.90		—			—		(12,441	)		7.28		—		—
December 31, 2018		585,742		$	7.76		567,002		$	12.97		—		$	—		84,771		$	8.33		500,000	$	7.20