Debt Arrangements - Additional Information (Detail)											1 Months Ended	3 Months Ended				9 Months Ended		12 Months Ended
		Mar. 30, 2020 USD ($)	Feb. 22, 2019 d	Mar. 14, 2018 USD ($)	Feb. 22, 2018 USD ($) d	Nov. 02, 2017 USD ($)	Oct. 27, 2017 USD ($)	Aug. 18, 2017 USD ($)	Aug. 02, 2017 USD ($)	Nov. 29, 2012 USD ($)	Feb. 28, 2015 USD ($)	Dec. 31, 2020 USD ($)	Sep. 30, 2020 USD ($) $ / shares shares	Sep. 30, 2019 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2020 USD ($) $ / shares	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)	Jul. 31, 2019	Mar. 31, 2019	Mar. 14, 2019 USD ($)	Feb. 12, 2018 USD ($)	Nov. 24, 2017 USD ($)	Oct. 26, 2017 USD ($)	Jul. 31, 2017 USD ($)	Jun. 21, 2013 USD ($)
Debt Instrument [Line Items]
Principal amount of long term debt							$ 240,700,000
Debt instrument, Maturity Date																2043-01
Debt service coverage ratio																				110.00%
Repayment of remaining outstanding principal balance							$ 231,000,000									$ 5,000,000
Current portion of long-term debt													$ 42,767,000			42,767,000		$ 61,976,000
Restricted cash													12,760,000			12,760,000		15,946,000
Leverage ratio							450.00%
Net proceeds from Permitted Capital Raising Transactions							$ 100,000,000
Debt issue discount costs							9,300,000
Deferred financing costs							$ 5,400,000
Percentage of repayment from net proceeds of asset sale		75.00%
Maximum amount of proceeds from asset sales to be used to pay the obligation		$ 5,000,000
Long term debt, fair value													49,140,000			49,140,000		47,277,000
Principal outstanding balance	[1],[2]												$ 583,549,000			$ 583,549,000		645,721,000
Maximum
Debt Instrument [Line Items]
Leverage ratio							575.00%
Aggregate amount of term loan facility							$ 165,700,000
5.75% Senior Subordinated Notes Due August 2023
Debt Instrument [Line Items]
Percentage of conversion of convertible notes													5.75%	5.75%		5.75%	5.75%				5.75%
MG Icon
Debt Instrument [Line Items]
Equity ownership percentage										50.00%
Hardy Way, LLC
Debt Instrument [Line Items]
Joint venture ownership percentage										85.00%
Zoo York brand
Debt Instrument [Line Items]
Ownership Percentage										100.00%
IBG Borrower
Debt Instrument [Line Items]
Termination of license generating with minimum royalty guarantees									$ 500,000
IBG Borrower | Minimum
Debt Instrument [Line Items]
Asset coverage ratio, minimum									125.00%
IBG Borrower | Maximum
Debt Instrument [Line Items]
Leverage ratio									450.00%
2012 Senior Secured Notes
Debt Instrument [Line Items]
Principal amount of long term debt										$ 600,000,000
Percentage of conversion of convertible notes										4.229%
Debt instrument, quarterly payment										$ 10,500,000
Debt instrument, frequency of payment																quarterly
Variable Funding Notes
Debt Instrument [Line Items]
Principal amount of long term debt										100,000,000
Net proceeds received from issuance of debt											$ 100,000,000
Line of credit, outstanding													$ 100,000,000			$ 100,000,000
Debt Instrument anticipated repayment year and month								2020-01
L/C commitment and the swingline commitment								$ 0
2013 Senior Secured Notes
Debt Instrument [Line Items]
Principal amount of long term debt																										$ 275,000,000
Percentage of conversion of convertible notes																										4.352%
Debt instrument, quarterly payment										$ 4,800,000
Debt instrument, frequency of payment																quarterly
Senior Secured Notes
Debt Instrument [Line Items]
Principal amount of long term debt													423,900,000			$ 423,900,000		438,100,000
Debt instrument, Maturity Date										2043-01						2043-01
Debt instrument description of interest																The Company did not repay or refinance the Securitization Notes prior to the anticipated repayment date, and as a result, during the first quarter of 2020, additional interest began accruing on amounts outstanding under the Securitization Notes at a rate equal to (A) in respect of the Variable Funding Notes, 5% per annum, (B) in respect of the 2012 Senior Secured Notes and the 2013 Senior Secured Notes, the greater of (1) 5% per annum and (2) a per annum interest rate equal to the excess, if any, by which the sum of (x) the yield to maturity (adjusted to a quarterly bond-equivalent basis), on the anticipated repayment date of the United States treasury security having a term closest to 10 years plus (y) 5% per annum plus (z) with respect to the 2012 Senior Secured Notes, 3.4% per annum, or with respect to the 2013 Senior Secured Notes, 3.14% per annum, exceeds the original interest rate.
Additional interest rate										5.00%
Anticipated repayment date										10 years
Repayment of remaining outstanding principal balance																$ 0
Mandatory principal prepayment																									$ 152,200,000
Current portion of long-term debt													10,900,000			10,900,000		42,700,000
Restricted cash													11,800,000			11,800,000		14,900,000
Interest expense for convertible notes													4,500,000	$ 5,200,000		13,900,000	$ 16,000,000
Long-term accrued interest expense for convertible notes													5,700,000	0		15,900,000	0
Non cash additional interest expense on convertible notes													$ 0	1,800,000		$ 1,100,000	5,200,000
Debt instrument, interest rate, effective percentage													10.90%			10.90%
2012 Senior Secured Notes
Debt Instrument [Line Items]
Excess interest rate on original interest rate										3.40%
2013 Senior Secured Notes
Debt Instrument [Line Items]
Excess interest rate on original interest rate										3.14%
Senior Secured Term Loan
Debt Instrument [Line Items]
Principal amount of long term debt							57,800,000		$ 300,000,000				$ 116,400,000			$ 116,400,000								$ 300,000,000
Repayment of remaining outstanding principal balance													44,700,000
Current portion of long-term debt													31,000,000			31,000,000		19,300,000
Interest expense for convertible notes													2,600,000	4,600,000		10,300,000	13,700,000
Non cash additional interest expense on convertible notes													$ 4,200,000	$ 1,400,000		$ 7,000,000	$ 4,100,000
Debt instrument, interest rate, effective percentage													11.60%			11.60%
Maturity date of credit agreement									Aug. 02, 2022
Margin applied to LIBOR									7.00%
Percentage of principal debt quarterly amortization									0.50%
Principal debt quarterly amortization commencement date									Sep. 30, 2017
Debt issue discount costs																$ 6,700,000		13,200,000
Estimated principal payments																							$ 12,000,000
Interest rate increase additional per annum				3.00%
Payment of unpaid principal and accrued interest of lenders				50.00%
Principal amount of long term debt													$ 109,700,000			109,700,000		162,400,000
Senior Secured Term Loan | Scenario Forecast
Debt Instrument [Line Items]
Repayment of remaining outstanding principal balance												$ 11,700,000
Senior Secured Term Loan | IBG Borrower
Debt Instrument [Line Items]
Equity ownership percentage				35.00%
Premium percentage of aggregate principal amount first year loan				5.00%
Premium percentage of aggregate principal amount second year loan				3.00%
Convertible Notes
Debt Instrument [Line Items]
Percentage of conversion of convertible notes															1.50%
Cash from escrow deposit returned to lenders							231,000,000
Payment from Escrow Account to acquire convertible notes															$ 59,200,000
Debt conversion original debt amount													0			0
Convertible Notes | 1.50% Senior Subordinated Notes Due March 15, 2018
Debt Instrument [Line Items]
Principal amount of long term debt					$ 125,000,000
Percentage of conversion of convertible notes					1.50%				1.50%
Convertible Notes | 5.75% Senior Subordinated Notes Due August 2023
Debt Instrument [Line Items]
Principal amount of long term debt					$ 125,000,000								$ 94,400,000			$ 94,400,000		$ 94,400,000
Percentage of conversion of convertible notes			5.75%		5.75%								5.75%	5.75%		5.75%	5.75%	5.75%
Interest expense for convertible notes													$ 1,400,000	$ 1,400,000		$ 4,100,000	$ 4,300,000
Maturity date of credit agreement					Aug. 15, 2023
Debt instrument, conversion rate																52.1919
Principal amount of each convertible note													$ 1,000			$ 1,000
Convertible notes, initial conversion price per share | $ / shares													$ 19.16			$ 19.16
Debt instrument convertible conversion price as percentage upon automatic conversion					5.75%
Debt instrument convertible conversion price as percentage upon mandatory conversion					5.75%
Debt instrument, convertible, threshold trading days | d					10
Volume weighted average price description																If the Company elects to pay all or a portion of a Conversion Make-Whole Payment in shares of common stock, the number of shares of common stock payable will be equal to the applicable Conversion Make-Whole Payment divided by the average of the 10 individual volume-weighted average prices for the 10-trading day period immediately preceding the applicable conversion date.
Debt instrument, convertible, threshold consecutive trading days | d			30
Debt instrument, redemption price, percentage			100.00%		100.00%
Debt instrument, redemption, description																each holder will have the right, at its option, to require the Company to repurchase for cash all or a portion of such holder’s 5.75% Convertible Notes at a fundamental change purchase price equal to 100% of the principal amount of the 5.75% Convertible Notes to be repurchased, together with interest accrued and unpaid to, but excluding, the fundamental change purchase date.
Debt instrument, restrictive covenants																The Company is subject to certain restrictive covenants pursuant to the 5.75% Convertible Note Indenture, including limitations on (i) liens, (ii) indebtedness, (iii) asset sales, (iv) restricted payments and investments, (v) prepayments of indebtedness and (vi) transactions with affiliates.
Long term debt, fair value													$ 49,100,000			$ 49,100,000		$ 47,300,000
Principal outstanding balance													$ 94,400,000			94,400,000		94,400,000
Stock Issued During Period, Shares, New Issues | shares													1,300
Convertible Notes | 5.75% Senior Subordinated Notes Due August 2023 | Fair Value Option
Debt Instrument [Line Items]
Long term debt, fair value													$ 49,100,000			$ 49,100,000		$ 47,300,000
First Delayed Draw Term Loan
Debt Instrument [Line Items]
Aggregate amount of term loan facility						$ 25,000,000	$ 25,000,000
Debt issue discount costs						1,000,000
Aggregate amount of term loan received in cash						$ 24,000,000
Second Delayed Draw Term Loan
Debt Instrument [Line Items]
Aggregate amount of term loan facility																					$ 140,700,000
Second Delayed Draw Term Loan | 1.50% Senior Subordinated Notes Due March 15, 2018
Debt Instrument [Line Items]
Percentage of conversion of convertible notes				1.50%
Maturity date of credit agreement				Mar. 15, 2018
Aggregate amount of term loan facility				$ 110,000,000
Senior Secured Term Loan Due 2022 | Minimum
Debt Instrument [Line Items]
Amortization rate per annum							2.00%
Senior Secured Term Loan Due 2022 | Maximum
Debt Instrument [Line Items]
Amortization rate per annum																			10.00%
5.75% Senior Subordinated Notes Due August 2023
Debt Instrument [Line Items]
Estimated principal payments																						$ 6,100,000
5.75% Senior Subordinated Notes Due August 2023 | Maximum
Debt Instrument [Line Items]
Percentage of conversion of convertible notes																						5.75%

[1] Carrying amounts include aggregate unamortized debt discount and debt issuance costs.

[2] Includes the 5.75% Convertible Notes accounted for under the fair value option. Refer to Note 7.