Quarterly Consolidated Financial Information - Unaudited (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Consolidated Financial Information (Unaudited)
Total revenue	$ 55,476	$ 51,461	$ 49,618	$ 50,719	$ 55,186	$ 57,730	$ 43,810	$ 41,336	$ 41,205	$ 45,519	$ 43,994	$ 43,340	$ 207,274	$ 198,062	$ 174,058
Net income (loss) attributable to common shareholders	$ 2,418	$ 3,985	$ 3,366	$ 4,011	$ 3,037	$ 2,551	$ (486)	$ 1,358	$ (491)	$ 1,000	$ 2,319	$ 4,352	$ 13,780	$ 6,460	$ 7,180
Basic earnings (loss) per common share (in dollars per share)	$ 0.40	$ 0.63	$ 0.50	$ 0.57	$ 0.39	$ 0.33	$ (0.06)	$ 0.17	$ (0.06)	$ 0.13	$ 0.29	$ 0.55	$ 2.10	$ 0.83	$ 0.91
Diluted earnings (loss) per common share (in dollars per share)	$ 0.39	$ 0.62	$ 0.49	$ 0.55	$ 0.38	$ 0.32	$ (0.06)	$ 0.17	$ (0.06)	$ 0.12	$ 0.28	$ 0.54	$ 2.05	$ 0.81	$ 0.88
Average common shares outstanding (in shares)	6,149	6,307	6,685	7,149	7,739	7,839	7,841	7,848	7,839	7,938	7,976	7,914	6,570	7,817	7,917
Diluted average common shares outstanding (in shares)	6,275	6,448	6,819	7,272	7,872	7,963	7,841	8,044	8,037	8,123	8,179	8,129	6,714	7,987	8,141