Summary Financial Information (Statements of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Gross profit	$ 66,209	$ 67,872	$ 73,493	$ 75,612	$ 76,045	$ 73,405	$ 75,900	$ 79,647	$ 283,186	$ 304,997	$ 285,061
Selling expenses									91,054	97,925	101,956
General and administrative expenses									77,880	83,567	85,605
Amortization of intangibles									12,942	14,900	15,552
Income from operations	$ 16,664	$ 20,886	$ 25,231	$ 27,043	$ 24,468	$ 6,646	$ 24,825	$ 13,503	89,824	69,442	68,331
Interest and debt expense									14,234	17,144	19,733
Investment (income) loss, net									(891)	(727)	(157)
Foreign currency exchange loss (gain), net									(1,514)	843	1,539
Other (income) expense, net									839	(716)	(2,469)
Income from continuing operations before income tax expense									77,156	52,898	49,685
Income tax expense									17,484	10,321	27,620
Net income									$ 59,672	$ 42,577	$ 22,065