Quarterly Results (Unaudited) - Summary of Unaudited Quarterly Results of Operations (Detail) - USD ($)	3 Months Ended								12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 207,233,000	$ 202,303,000	$ 195,522,000	$ 190,253,000	$ 185,443,000	$ 179,386,000	$ 177,426,000	$ 176,307,000	$ 795,311,000	$ 718,562,000	$ 646,230,000
Gross Profit	43,403,000	42,160,000	44,252,000	41,878,000	41,951,000	40,345,000	36,094,000	39,869,000	171,693,000	158,259,000	152,114,000
Net Income (Loss)	$ 19,454,000	$ 17,095,000	$ 19,898,000	$ 19,805,000	$ 18,169,000	$ 16,849,000	$ 14,656,000	$ 16,691,000	$ 76,252,000	$ 66,365,000	$ 66,410,000
Net Income per Basic Common Share	$ 1.13	$ 1	$ 1.16	$ 1.16	$ 1.06	$ 0.98	$ 0.84	$ 0.95	$ 4.45	$ 3.83	$ 3.74
Net Income per Diluted Common Share	$ 1.12	$ 0.99	$ 1.15	$ 1.14	$ 1.04	$ 0.96	$ 0.83	$ 0.94	$ 4.4	$ 3.77	$ 3.66