Quarterly Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 162,676	$ 135,483	$ 127,854	$ 106,569	$ 129,455	$ 115,813	$ 118,716	$ 106,575	$ 532,582	$ 470,559
Gross profit	33,440	19,059	19,083	13,436	22,472	17,167	17,153	18,271	85,018	75,063	$ 94,575
Net income (loss)	$ 8,739	$ 9,061	$ (1,217)	$ (2,846)	$ 3,261	$ (2,041)	$ (225)	$ (364)	$ 13,737	$ 631	$ 16,660
Earnings (loss) per share
Basic (in dollars per share)	$ 0.74	$ 0.77	$ (0.10)	$ (0.24)	$ 0.28	$ (0.17)	$ (0.02)	$ (0.03)	$ 1.16	$ 0.05	$ 1.43
Diluted (in dollars per share)	$ 0.73	$ 0.76	$ (0.10)	$ (0.24)	$ 0.28	$ (0.17)	$ (0.02)	$ (0.03)	$ 1.15	$ 0.05	$ 1.42
Decrease in valuation allowance		$ 5,900							$ (6,700)
Gain on sale of non-core business		$ 2,000							2,006	$ 0	$ 0
Revenue recognized related to settlement of a claim for cost overruns from prior years	$ 2,500								$ 39,100