Quarterly Results (Unaudited) - Summary of Unaudited Quarterly Results of Operations (Detail) - USD ($)	3 Months Ended								12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 171,359,000	$ 164,508,000	$ 157,743,000	$ 152,620,000	$ 145,510,000	$ 141,506,000	$ 136,028,000	$ 129,600,000	$ 646,230,000	$ 552,644,000	$ 592,225,000
Gross Profit	43,052,000	35,188,000	36,661,000	37,213,000	35,719,000	30,893,000	30,503,000	26,509,000	152,114,000	123,624,000	125,921,000
Net income	$ 19,637,000	$ 13,858,000	$ 16,072,000	$ 16,843,000	$ 14,809,000	$ 11,380,000	$ 11,865,000	$ 8,302,000	$ 66,410,000	$ 46,356,000	$ 47,377,000
Earnings Per Share, Basic	$ 1.11	$ 0.78	$ 0.90	$ 0.94	$ 0.83	$ 0.64	$ 0.66	$ 0.46	$ 3.74	$ 2.59	$ 2.59
Earnings Per Share, Diluted	$ 1.09	$ 0.76	$ 0.88	$ 0.92	$ 0.81	$ 0.63	$ 0.65	$ 0.46	$ 3.66	$ 2.55	$ 2.55