Earnings Per Common Share - Schedule of Earnings Per Share (Detail) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share [Abstract]
Earnings from continuing operations	$ 9,236	$ 8,523	$ 30,661	$ 19,985
Less dividend equivalents attributable to RSUs outstanding	(111)	(96)	(379)	(273)
Earnings from continuing operations attributable to common shareholders	9,125	8,427	30,282	19,712
(Loss) from discontinued operations	(432)	(1,488)	(578)	(2,468)
Less dividend equivalents attributable to RSUs outstanding	0	0	0	0
(Loss) from discontinued operations attributable to common shareholders	(432)	(1,488)	(578)	(2,468)
Net earnings attributable to common shareholders used for basic and diluted earnings per share calculation	$ 8,693	$ 6,939	$ 29,704	$ 17,244
Basic and diluted	33,776	33,422	33,716	33,420
RSUs outstanding at the end of the period	430	401	430	401