Weighted Average Common Shares (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Numerators:
Net income attributable to common shareholders	$ 14,821	$ 13,116	$ 27,667	$ 29,902
Income attributable to unvested participating securities	(24)	(8)	(45)	(19)
Net income attributable to common shareholders used in calculating earnings per share	$ 14,797	$ 13,108	$ 27,622	$ 29,883
Denominators:
Weighted average common shares for basic earnings per share (in shares)	65,089	65,039	65,082	65,035
Effect of dilutive securities: unvested share awards (in shares)	2	4	5	7
Weighted average common shares for diluted earnings per share (in shares)	65,091	65,043	65,087	65,042
Net income attributable to common shareholders per common share - basic	$ 0.23	$ 0.20	$ 0.42	$ 0.46
Net income attributable to common shareholders per common share - diluted	$ 0.23	$ 0.20	$ 0.42	$ 0.46