Quarterly Financial Data (Unaudited) - (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2018
Total Revenue	$ 201,940	$ 130,588	$ 126,012	$ 140,177	$ 197,157	$ 148,296	$ 138,023	$ 113,206	$ 598,717	$ 596,682	$ 507,566
Gross profit	186,782	114,883	110,486	124,959	181,667	133,936	123,284	99,979	537,110	538,866	456,922
Income from operations	116,296	44,734	42,939	53,390	112,611	71,143	61,358	36,027	257,359	281,139	207,928
Net income	$ 94,530	$ 41,826	$ 39,801	$ 53,514	$ 105,994	$ 61,951	$ 56,454	$ 36,966	$ 229,671	$ 261,362	$ 281,234
Net income per common share:
Basic (in dollars per share)	$ 1.40	$ 0.62	$ 0.58	$ 0.78	$ 1.54	$ 0.89	$ 0.80	$ 0.52	$ 3.38	$ 3.74	$ 3.90
Diluted (in dollars per share)	$ 1.39	$ 0.61	$ 0.58	$ 0.77	$ 1.52	$ 0.88	$ 0.79	$ 0.51	$ 3.34	$ 3.69	$ 3.85
Weighted average shares outstanding:
Basic (in shares)	67,634	67,806	68,114	68,441	68,839	69,423	70,428	70,988	68,000	69,925	72,140
Diluted (in shares)	68,176	68,482	68,844	69,317	69,638	70,160	71,148	72,015	68,727	70,787	72,956
Previously Reported [Member]
Total Revenue		$ 132,027	$ 124,732	$ 134,091	$ 195,769	$ 147,984	$ 140,423	$ 114,169		$ 598,345	$ 518,859
Gross profit		116,322	109,206	118,873	180,279	133,624	125,684	100,942		540,529	468,215
Income from operations		46,173	41,659	47,304	111,223	70,831	63,758	36,990		282,802	219,221
Net income		$ 43,521	$ 38,275	$ 46,284	$ 103,865	$ 61,587	$ 59,217	$ 38,066		$ 262,734	$ 293,703
Net income per common share:
Basic (in dollars per share)		$ 0.64	$ 0.56	$ 0.68	$ 1.51	$ 0.89	$ 0.84	$ 0.54		$ 3.76	$ 4.07
Diluted (in dollars per share)		$ 0.64	$ 0.56	$ 0.67	$ 1.49	$ 0.88	$ 0.83	$ 0.53		$ 3.71	$ 4.03
Weighted average shares outstanding:
Basic (in shares)		67,806	68,114	68,441	68,839	69,423	70,428	70,988
Diluted (in shares)		68,482	68,844	69,317	69,638	70,160	71,148	72,015
Restatement Adjustment [Member]
Total Revenue		$ (1,439)	$ 1,280	$ 6,086	$ 1,388	$ 312	$ (2,400)	$ (963)		$ (1,663)	$ (11,293)
Gross profit		(1,439)	1,280	6,086	1,388	312	(2,400)	(963)		(1,663)	(11,293)
Income from operations		(1,439)	1,280	6,086	1,388	312	(2,400)	(963)		(1,663)	(11,293)
Net income		$ (1,695)	$ 1,526	$ 7,230	$ 2,129	$ 364	$ (2,763)	$ (1,100)		$ (1,372)	$ (12,469)
Net income per common share:
Basic (in dollars per share)		$ (0.02)	$ 0.02	$ 0.10	$ 0.03	$ 0	$ (0.04)	$ (0.02)		$ (0.02)	$ (0.17)
Diluted (in dollars per share)		$ (0.03)	$ 0.02	$ 0.10	$ 0.03	$ 0	$ (0.04)	$ (0.02)		$ (0.02)	$ (0.18)
Weighted average shares outstanding:
Basic (in shares)		0	0	0	0	0	0	0
Diluted (in shares)		0	0	0	0	0	0	0