Income Taxes - Federal State and Local Income Tax Expense (Details) - USD ($) $ in Thousands	3 Months Ended												6 Months Ended	12 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2017
Current Income Tax Expense (Benefit)
Federal														$ 13,185	$ (9,439)	$ 764
State and Local														(81)	1,152	638
Total Current Income Tax Expense (Benefit)														13,104	(8,287)	1,402
Deferred Income Tax Expense (Benefit)
Federal														(85,022)	31,263	(2,210)
State and Local														(2,220)	(573)	1,905
Total Deferred Income Tax Expense (Benefit)														(87,242)	30,690	(305)
Total Income Tax Expense (Benefit)	$ (2,544)	$ 1,359	$ 2,647	$ (75,600)	$ (883)	$ (2,275)	$ 18,138	$ 7,423	$ 3,100	$ 7,337	$ 3,542	$ (12,882)		$ (74,138)	$ 22,403	$ 1,097
Reconciliation of the company's federal statutory tax rate to its effective rate
Federal income tax at statutory rate (as a percent)													21.00%	21.00%	28.10%	35.00%
State and local income tax, net (as a percent)														0.50%	0.60%	293.60%
Nondeductible expenses (as a percent)														(0.10%)	0.20%	45.40%
Foreign rate differential (as a percent)														(0.40%)	0.40%	49.90%
Income tax credits (as a percent)														0.50%	(1.40%)	(160.90%)
Domestic production activity deduction (as a percent)															(1.50%)
Unrecognized tax benefits														0.10%	(6.70%)
Change in tax laws (as a percent)															25.60%
Excess tax benefits on share-based compensation (as a percent)														(0.30%)	(0.30%)	(134.30%)
Other (as a percent)														0.10%	(1.20%)	70.80%
Effective income tax rate (as a percent)														21.40%	43.80%	199.50%
Deferred tax assets:
Accrued expenses					1,085								$ 1,085		$ 1,085
Share-based compensation expense	4,134				4,158								4,158	$ 4,134	4,158
Reserve for returns	12,014				9,342								9,342	12,014	9,342
Reserves for accounts receivable and inventory	8,208				5,425								5,425	8,208	5,425
Intangible impairment					1,337								1,337		1,337
Federal net operating loss	324				402								402	324	402
State net operating loss	6,479				4,495								4,495	6,479	4,495
Impairment on Cody note receivable	1,161				1,175								1,175	1,161	1,175
Accumulated amortization on intangible assets	76,401				10,868								10,868	76,401	10,868
Foreign net operating loss	1,792				880								880	1,792	880
Interest Carryforward	11,008													11,008
Other	2,506				404								404	2,506	404
Total deferred tax asset	124,027				39,571								39,571	124,027	39,571
Valuation allowance	(13,549)				(8,120)								(8,120)	(13,549)	(8,120)
Total deferred tax asset less valuation allowance	110,478				31,451								31,451	110,478	31,451
Deferred tax liabilities:
Prepaid expenses	182				118								118	182	118
Property, plant and equipment	991				9,231								9,231	991	9,231
Other					39								39		39
Total deferred tax liability	1,173				9,388								9,388	1,173	9,388
Net deferred tax asset	$ 109,305				$ 22,063								$ 22,063	$ 109,305	$ 22,063