Debt Arrangements - Additional Information (Detail) $ / shares in Units, shares in Millions																	1 Months Ended							3 Months Ended	9 Months Ended	12 Months Ended
		Feb. 22, 2018 USD ($) d	Dec. 07, 2017 USD ($)	Nov. 02, 2017 USD ($)	Oct. 27, 2017 USD ($)	Aug. 18, 2017 USD ($)	Aug. 02, 2017 USD ($)	Jun. 30, 2017 USD ($)	Jun. 01, 2016 USD ($)	Apr. 04, 2016 USD ($)	Mar. 07, 2016 USD ($)	Mar. 18, 2013 USD ($) d $ / shares shares	Mar. 13, 2013 USD ($) $ / shares shares	Mar. 12, 2013 $ / shares	Nov. 29, 2012 USD ($)	May 23, 2011 USD ($)	Jul. 31, 2017 USD ($)	Jan. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Apr. 30, 2016 USD ($)	Feb. 28, 2015 USD ($)	Jul. 31, 2014 USD ($)	Mar. 31, 2013 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($) shares	Dec. 31, 2015 USD ($)	Jul. 31, 2019	Mar. 14, 2018 USD ($)	Feb. 12, 2018 USD ($)	Nov. 24, 2017 USD ($)	Jul. 31, 2016 USD ($)	Jun. 30, 2016 USD ($)	Jan. 07, 2016 $ / shares	Jun. 21, 2013 USD ($)
Debt Instrument [Line Items]
Principal amount of long term debt					$ 240,700,000			$ 0
Net proceeds received from issuance of debt																										$ 307,030,000	$ 300,000,000
Payments of securitized financing transaction																										7,145,000	35,754,000	$ 496,000
Payment for the acquisition of Brand																										212,000	268,000	199,000
Payment of long-term debt																										824,867,000	253,490,000	61,124,000
Deferred financing costs					5,400,000																			$ 200,000		200,000
Loss on extinguishment of debt																										(20,939,000)	(5,903,000)
Debt issue discount costs					9,300,000
Current portion of long-term debt																			$ 160,435,000					44,349,000		44,349,000	160,435,000
Restricted cash																			177,269,000					48,766,000		48,766,000	177,269,000
Cash interest expense for convertible notes																										12,400,000	25,600,000
Long-term debt, including current portion, Carrying Amount	[1]																		1,254,160,000					800,842,000		800,842,000	1,254,160,000
Debt instrument, cash paid to repurchase convertible notes																										58,810,000	178,973,000
Repurchase of equity portion of convertible notes																											1,164,000
Non cash additional interest expense on convertible notes																										$ 7,349,000	21,745,000	31,455,000
Percentage of principal debt quarterly amortization							0.50%
Principal debt quarterly amortization commencement date							Sep. 30, 2017
Repayments of debt on principle amount			$ 5,000,000		231,000,000
Deutsche Bank AG
Debt Instrument [Line Items]
Principal amount of long term debt					$ 300,000,000		$ 300,000,000
Leverage ratio					4.50%
Net proceeds from Permitted Capital Raising Transactions					$ 100,000,000
Financial covenant compliance on a pro forma basis																										the Company raising additional funds through various sources (and/or achieving a reduction in the outstanding principal amount of the 2018 Notes) in an aggregate amount of at least $100 million which will be utilized to repay the 2018 Notes and provide at least $25 million of additional cash to enhance liquidity and be used for general corporate purposes, (ii) the Company being in financial covenant compliance, on a pro forma basis as of the time of the requested borrowing and on a projected basis for the succeeding 12 months
Projected Succeding period of borrowings					12 months
Estimated principal payments																																$ 12,000,000
Subsequent Event
Debt Instrument [Line Items]
Aggregate amount of term loan facility		$ 110,000
Maturity date of credit agreement		Mar. 15, 2018
Minimum
Debt Instrument [Line Items]
Selling price per share of common stock | $ / shares																																			$ 4.53
Minimum | Subsequent Event
Debt Instrument [Line Items]
Net proceeds received from issuance of debt		$ 100,000,000
Maximum
Debt Instrument [Line Items]
Selling price per share of common stock | $ / shares																																			$ 59.08
Maximum | Deutsche Bank AG
Debt Instrument [Line Items]
Aggregate amount of term loan facility					$ 165,700,000
Leverage ratio					5.75%
5.75% Senior Subordinated Notes Due August 2023 | Subsequent Event | Deutsche Bank AG
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage																															5.75%
5.75% Senior Subordinated Notes Due August 2023 | Maximum | Subsequent Event | Deutsche Bank AG
Debt Instrument [Line Items]
Estimated principal payments																															$ 6,100,000
MG Icon
Debt Instrument [Line Items]
Equity ownership percentage															50.00%
Peanuts Holdings, LLC
Debt Instrument [Line Items]
Joint venture ownership percentage															80.00%
Hardy Way
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]
Equity ownership percentage											35.00%
Termination of license generating with minimum royalty guarantees							$ 500,000																	5,000,000		$ 5,000,000
Premium percentage of aggregate principal amount first two years loan											3.00%
Premium percentage of aggregate principal amount third year loan											3.00%
Premium percentage of aggregate principal amount fourth year loan											1.00%
IBG Borrower | Minimum
Debt Instrument [Line Items]
Asset coverage ratio, minimum							1.25%				1.25%
IBG Borrower | Maximum
Debt Instrument [Line Items]
Leverage ratio							4.50%				4.50%
Ice Cream Trademarks
Debt Instrument [Line Items]
Equity ownership percentage																																				50.00%
2012 Senior Secured Notes
Debt Instrument [Line Items]
Principal amount of long term debt															$ 600,000,000
Debt instrument, quarterly payment															$ 10,500,000
Debt instrument, frequency of payment																										quarterly
Excess interest rate on original interest rate															3.40%
Proceeds from issuance of debt instrument															$ 150,400,000
Payments of securitized financing transaction															20,900,000
2012 Senior Secured Notes | Umbro
Debt Instrument [Line Items]
Payment for the acquisition of Brand															218,300,000
Variable Funding Notes
Debt Instrument [Line Items]
Principal amount of long term debt															100,000,000									100,000,000		$ 100,000,000
Net proceeds received from issuance of debt																					$ 100,000,000
Commitment fee on the unused portion of the variable funding notes facility																					0.50%
Debt Instrument anticipated repayment year and month						2020-01															2018-01
Additional interest rate																					5.00%
L/C commitment and the swingline commitment						$ 0
Long-term debt, including current portion, Carrying Amount	[2]																		100,000,000					91,363,000		$ 91,363,000	100,000,000
2013 Senior Secured Notes
Debt Instrument [Line Items]
Principal amount of long term debt																																				$ 275,000,000
Debt instrument, quarterly payment															$ 4,800,000
Debt instrument, frequency of payment																										quarterly
Excess interest rate on original interest rate															3.14%
Payments of securitized financing transaction															$ 7,200,000
Senior Secured Notes
Debt Instrument [Line Items]
Principal amount of long term debt																			751,800,000					508,200,000		$ 508,200,000	751,800,000
Debt Instrument anticipated repayment year and month															2020-01
Additional interest rate															5.00%
Debt instrument, Maturity Date															2043-01
Debt instrument description of interest																										If the Co-Issuers have not repaid or refinanced the Senior Secured Notes prior to the anticipated repayment date, additional interest will accrue on the Senior Secured Notes at a rate equal to the greater of (A) 5% per annum and (B) a per annum interest rate equal to the excess, if any, by which the sum of (i) 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 (ii) 5% plus (iii) with respect to the 2012 Senior Secured Notes, 3.4%, or with respect to the 2013 Senior Secured Notes, 3.14%, exceeds the original interest rate.
Anticipated repayment date															10 years
Payment of long-term debt																						$ 1,600,000
Debt instrument, annual principal prepayment																		$ 36,700,000
Deferred financing costs																		500,000
Loss on extinguishment of debt																	$ (2,300,000)	(500,000)
Mandatory principal prepayment																	152,200,000
Debt issue discount costs																	2,000,000
Prepayment penalty																	300,000
Current portion of long-term debt																			42,700,000					42,700,000		$ 42,700,000	42,700,000
Restricted cash																			112,400,000					29,900,000		29,900,000	112,400,000
Cash interest expense for convertible notes																										28,700,000	33,600,000	34,800,000
Long-term debt, including current portion, Carrying Amount																			$ 651,784,000					$ 408,174,000		$ 408,174,000	651,784,000
2012 Senior Secured Notes
Debt Instrument [Line Items]
Debt instrument, quarterly principal payments																		9,900,000
Debt instrument, decrease in quarterly principal payments																	7,300,000
2013 Senior Secured Notes
Debt Instrument [Line Items]
Debt instrument, quarterly principal payments																		4,500,000
Debt instrument, decrease in quarterly principal payments																	$ 3,400,000
Convertible Notes | Deutsche Bank AG
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage																								1.50%		1.50%
Cash from escrow deposit returned to lenders					$ 231,000,000
Payment from Escrow Account to acquire convertible notes																									$ 59,200,000
Convertible Notes | 1.50% Senior Subordinated Notes Due March 15, 2018
Debt Instrument [Line Items]
Principal amount of long term debt												$ 400,000,000												$ 236,200,000		$ 236,200,000
Net proceeds received from issuance of debt												$ 390,600,000
Cash interest expense for convertible notes																										$ 4,200,000	$ 5,200,000	$ 6,000,000
Debt instrument, interest rate, stated percentage												1.50%							1.50%					1.50%		1.50%	1.50%	1.50%
Debt instrument, payment terms																										The 1.50% Convertible Notes bear interest at an annual rate of 1.50%, payable semi-annually in arrears on March 15 and September 15 of each year, beginning on September 15, 2013
Debt instrument, effective interest rate												6.50%
Debt instrument, conversion rate												32.4052
Principal amount of each convertible note												$ 1,000
Convertible notes, initial conversion price per share | $ / shares												$ 30.86
Long-term debt, including current portion, Carrying Amount	[3]																		$ 277,518,000					$ 233,898,000		$ 233,898,000	$ 277,518,000
Debt instrument, par value of notes repurchased																			104,900,000					58,900,000		58,900,000	104,900,000						$ 53,200,000	$ 51,700,000
Debt instrument, cash paid to repurchase convertible notes																										59,300,000	36,700,000
Debt instrument, gain (loss) on repurchase of convertible notes																										1,500,000	9,600,000
Repurchase of equity portion of convertible notes																											1,200,000
Non cash additional interest expense on convertible notes																										12,800,000	14,600,000	$ 16,200,000
Sold warrants, shares of common stock | shares													13.0
Sold warrants, shares of common stock strike price per share | $ / shares													$ 35.5173
Sold warrants, shares of common stock exercise date													Jun. 18, 2018
Sold warrants, shares of common stock expiring date													Sep. 01, 2018
Proceeds received from sale of sold warrants													$ 57,700,000
Adjustments to additional paid in capital due convertible note hedge and warrants																							$ 3,000,000
Convertible notes, warrant strike price | $ / shares														$ 35.5173
Percentage of premiums														52.50%
Selling price per share of common stock | $ / shares														$ 23.29
Convertible Notes | 1.50% Senior Subordinated Notes Due March 15, 2018 | Long | Call Option
Debt Instrument [Line Items]
Convertible notes, common stock option shares | shares												13.0
Payment for the purchased call option													84,100,000
Deferred income tax related to convertible notes													$ 29,400,000						5,600,000					600,000		600,000	$ 5,600,000
Convertible Notes | 1.50% Senior Subordinated Notes Due March 15, 2018 | Deutsche Bank AG
Debt Instrument [Line Items]
Proceeds from deposits in escrow account to repay																								240,000,000
Proceeds from initial escrow funds to repurchase outstanding debt																										59,000,000
Additional amount held in escrow																								300,000,000		300,000,000
Line of credit remaining outstanding principal amount																								236,000,000		$ 236,000,000
Convertible Notes | 1.50% Senior Subordinated Notes Due March 15, 2018 | Common Stock
Debt Instrument [Line Items]
Debt instrument, shares issued to repurchase convertible notes | shares																											7.4
Convertible Notes | 1.50% Senior Subordinated Notes Due March 15, 2018 | Subsequent Event
Debt Instrument [Line Items]
Principal amount of long term debt		$ 125,000,000
Debt instrument, interest rate, stated percentage		1.50%																												1.50%
Maturity date of credit agreement		Mar. 15, 2018
Convertible Notes | 1.50% Senior Subordinated Notes Due March 15, 2018 | Scenario 1
Debt Instrument [Line Items]
Debt instrument, convertible, threshold trading days | d												20
Debt instrument, convertible, threshold consecutive trading days | d												30
Debt instrument, redemption price, percentage																										100.00%
Debt instrument, redemption, description																										price equal to 100% of the principal amount of the 1.50% Convertible Notes, plus accrued and unpaid interest, if any
Convertible Notes | 1.50% Senior Subordinated Notes Due March 15, 2018 | Scenario 2
Debt Instrument [Line Items]
Debt instrument, convertible, threshold trading days | d												5
Debt instrument, convertible, threshold consecutive trading days | d												5
Convertible Notes | 1.50% Senior Subordinated Notes Due March 15, 2018 | Minimum
Debt Instrument [Line Items]
Percentage of closing price to trigger debt conversion												130.00%
Convertible Notes | 1.50% Senior Subordinated Notes Due March 15, 2018 | Maximum
Debt Instrument [Line Items]
Percentage of closing price to trigger debt conversion												98.00%
Convertible Notes | 5.75% Senior Subordinated Notes Due August 2023 | Subsequent Event
Debt Instrument [Line Items]
Debt instrument, convertible, threshold trading days | d		10
Debt instrument, convertible, threshold consecutive trading days | d		30
Debt instrument, redemption price, percentage		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.
Convertible Notes | 5.75% Senior Subordinated Notes Due August 2023 | Scenario, Plan | Subsequent Event
Debt Instrument [Line Items]
Principal amount of long term debt		$ 125,000,000
Debt instrument, interest rate, stated percentage		5.75%
Convertible Notes | 2.50% Senior Subordinated Notes Due June 2016
Debt Instrument [Line Items]
Principal amount of long term debt																$ 300,000,000
Net proceeds received from issuance of debt																$ 291,600,000
Cash interest expense for convertible notes																										$ 0	$ 3,000,000	7,500,000
Debt instrument, interest rate, stated percentage										2.50%						2.50%
Debt instrument, par value of notes repurchased																				$ 143,900,000
Debt instrument, cash paid to repurchase convertible notes																				$ 145,600,000
Debt instrument, gain (loss) on repurchase of convertible notes																											(1,200,000)
Non cash additional interest expense on convertible notes																										0	4,500,000	12,700,000
Repayment of remaining outstanding balance of convertible notes upon maturity									$ 156,100,000
Second Delayed Draw Term Loan | Subsequent Event
Debt Instrument [Line Items]
Aggregate amount of term loan facility																														$ 110,000,000
Second Delayed Draw Term Loan | Scenario, Forecast | Deutsche Bank AG
Debt Instrument [Line Items]
Aggregate amount of term loan facility																														$ 140,700,000
Senior Secured Term Loan
Debt Instrument [Line Items]
Principal amount of long term debt								0			$ 300,000,000
Debt instrument, annual principal prepayment																			28,700,000					28,700,000		28,700,000	28,700,000
Deferred financing costs																			1,000,000					800,000		800,000	1,000,000
Loss on extinguishment of debt																			7,400,000							(5,000,000)
Mandatory principal prepayment																		23,500,000
Debt issue discount costs																			2,100,000							$ 1,700,000
Long-term debt, including current portion, Carrying Amount	[4]																		244,906,000								244,906,000
Maturity date of credit agreement											Mar. 07, 2021
Margin applied to LIBOR											10.00%
Net proceeds received from issuance of debt										$ 264,200,000
Premium prepayment of aggregate principal amount																			4,300,000
Percentage of principal debt amortization											5.00%
Asset coverage ratio, minimum											1.65%
Interest rate increase additional per annum											3.00%
Payment of unpaid principal and accrued interest of lenders											50.00%
Voluntary prepayment amount																		23,000,000
Voluntary prepayment premium																		3,400,000
Additional mandatory prepayment premium																		$ 3,400,000
Senior Secured Term Loan | Discontinued Operations | Entertainment
Debt Instrument [Line Items]
Debt instrument, annual principal prepayment								140,000,000
Deferred financing costs								4,700,000
Debt issue discount costs								9,400,000
Premium prepayment of aggregate principal amount								15,200,000
Senior Secured Term Loan | Continuing Operations
Debt Instrument [Line Items]
Deferred financing costs								2,300,000
Debt issue discount costs								4,400,000
Voluntary prepayment amount								66,000,000
Voluntary prepayment premium								$ 7,200,000
Senior Secured Term Loan | Accounts Payable And Accrued Liabilities
Debt Instrument [Line Items]
Accrued Expenses																			$ 6,800,000								6,800,000
Senior Secured Term Loan | LIBOR
Debt Instrument [Line Items]
LIBOR floor											1.50%
Senior Secured Term Loan | IBG Borrower
Debt Instrument [Line Items]
Percentage of principal debt amortization											25.00%
Asset coverage ratio, minimum											1.25%
Principals of debt amortization terms																										Borrowings under the Senior Secured Term Loan amortized yearly at 5% of principal as long as the applicable asset coverage ratio, as defined in the Credit Agreement, remained greater than or equal to 1.65:1.00 as of the end of each fiscal quarter and IBG Borrower timely delivered a compliance certificate to Cortland after each fiscal quarter. If IBG Borrower’s asset coverage ratio measured as of the end of a certain fiscal quarter was 1.25:1.00 or greater but less than 1.45:1.00, or 1.45:1.00 or greater but less than 1.65:1.00, IBG Borrower was obligated to pay during the subsequent quarter amortization at 25% per annum, or 15% per annum,
Asset coverage ratio, maximum - Range one											1.45%
Asset coverage ratio, minimum - Range two											1.45%
Asset coverage ratio, maximum - Range two											1.65%
Percentage of principal debt amortization - Range two											15.00%
Percentage of principal debt amortization on default											25.00%
2017 Senior Secured Term Loan Due 2022
Debt Instrument [Line Items]
Principal amount of long term debt					57,800,000		$ 300,000,000																	82,800,000		$ 82,800,000
Deferred financing costs					800,000
Loss on extinguishment of debt					8,800,000
Debt issue discount costs																										8,000,000
Current portion of long-term debt																								1,700,000		1,700,000
Cash interest expense for convertible notes																										7,100,000	0	0
Long-term debt, including current portion, Carrying Amount	[5]																							74,813,000		74,813,000
Maturity date of credit agreement							Aug. 02, 2022
Margin applied to LIBOR							7.00%
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																								$ 74,800,000		74,800,000
2017 Senior Secured Term Loan Due 2022 | 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%
First Delayed Draw Term Loan
Debt Instrument [Line Items]
Debt issue discount costs				$ 1,000,000
Aggregate amount of term loan facility				25,000,000
Aggregate amount of term loan received in cash				$ 24,000,000
First Delayed Draw Term Loan | Deutsche Bank AG
Debt Instrument [Line Items]
Aggregate amount of term loan facility					$ 25,000,000
Senior Secured Term Loan Due 2022
Debt Instrument [Line Items]
Non cash additional interest expense on convertible notes																										$ 9,900,000	$ 0	$ 0
Senior Secured Term Loan Due 2022 | Minimum | Deutsche Bank AG
Debt Instrument [Line Items]
Amortization rate per annum					2.00%
Senior Secured Term Loan Due 2022 | Maximum | Scenario, Forecast | Deutsche Bank AG
Debt Instrument [Line Items]
Amortization rate per annum																													10.00%
Second Delayed Draw Term Loan | Minimum | Deutsche Bank AG
Debt Instrument [Line Items]
Additional funds to be raised through various sources					$ 100,000,000
Additional funds to enhance liquidity for general corporate purpose					$ 25,000,000

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

[2] On August 18, 2017, the Company entered into an amendment of its Variable Funding Note which extended the anticipated repayment date for the Variable Funding Notes from January 2018 to January 2020. See below for further details

[3] During FY 2016, the Company repurchased a total of $104.9 million par value (of which $51.7 million and $53.2 million were purchased in June 2016 and July 2016, respectively) of the 1.50% Convertible Notes. During FY 2017, the Company repurchased a total of $58.9 million par value of the 1.50% Convertible Notes. See below for further details. On February 22, 2018, the Company exchanged $125 million of aggregate principal amount of 1.50% Convertible Notes for $125 million of aggregate principal amount of 5.75% Convertible Notes, and on March 14, 2018, the Company drew down $110 million under the Second Delayed Draw Term Loan and used those proceeds, along with cash on hand, to make a payment to the trustee under the indenture governing the 1.50% Convertible Notes to repay the remaining 1.50% Convertible Notes at maturity on March 15, 2018.

[4] In December 2016, the Company made a mandatory principal prepayment of $28.7 million on its Senior Secured Term Loan. See below for further details. On June 30, 2017, the Company repaid the remaining outstanding principal balance of the Senior Secured Term Loan and accordingly, the Company wrote off the remaining portion of the deferred financing costs and original issue discount associated with the debt facility. See below for further details.

[5] On August 2, 2017, the Company entered into the DB Credit Agreement for an aggregate principal amount of $300 million. See below for further details.