Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Consolidated Statements of Income [Abstract]
Revenue	$ 560,615	$ 704,055	$ 1,165,514	$ 1,381,081
Cost of sales	148,100	171,975	309,599	342,541
Gross profit	412,515	532,080	855,915	1,038,540
Operating expenses:
Selling expenses	219,426	280,589	462,125	556,554
General and administrative expenses	141,562	166,115	290,118	333,697
Total operating expenses	360,988	446,704	752,243	890,251
Operating income	51,527	85,376	103,672	148,289
Other income (expense), net	(8,640)	(4,012)	(10,093)	(2,430)
Income before provision for income taxes	42,887	81,364	93,579	145,859
Provision for income taxes	8,650	22,026	20,626	39,091
Net income	$ 34,237	$ 59,338	$ 72,953	$ 106,768
Net income per share (Note 6):
Basic (in dollars per share)	$ 0.68	$ 1.18	$ 1.45	$ 2.12
Diluted (in dollars per share)	$ 0.67	$ 1.15	$ 1.43	$ 2.06
Weighted-average common shares outstanding:
Basic (in shares)	50,368	50,115	50,181	50,409
Diluted (in shares)	50,960	51,557	50,959	51,850