Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2020	Sep. 30, 2019
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 50,691	$ 51,459	$ 54,798	$ 52,238	$ 54,183	$ 38,700	$ 33,756	$ 33,752	$ 209,185	$ 160,391
Income from operations	2,698	3,800	3,837	3,126	3,394	1,690	2,327	2,557	13,461	9,968
Interest expense, net	(781)	(813)	(906)	(941)	(1,190)	(562)	(545)	(177)	(3,441)	(2,473)
Income before income taxes	1,917	2,987	2,931	2,185	2,204	1,128	1,782	2,380	10,020	7,495
Income tax expense	554	863	855	634	639	325	517	690	2,906	2,171
Net income	$ 1,363	$ 2,124	$ 2,076	$ 1,551	$ 1,565	$ 803	$ 1,265	$ 1,690	$ 7,114	$ 5,324
Basic (in dollars per share)	$ 0.11	$ 0.17	$ 0.17	$ 0.13	$ 0.13	$ 0.07	$ 0.11	$ 0.14	$ 0.58	$ 0.44
Diluted (in dollars per share)	$ 0.10	$ 0.16	$ 0.16	$ 0.12	$ 0.12	$ 0.06	$ 0.10	$ 0.13	$ 0.54	$ 0.41