Long-Term Debt - Additional Information (Detail)		3 Months Ended			9 Months Ended
	Mar. 30, 2017 USD ($)	Jun. 30, 2017 USD ($) Swap	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	May 14, 2013	Dec. 01, 2009 USD ($)
Debt Instrument [Line Items]
Long-term debt				$ 1,598,001,000	$ 1,550,972,000
Outstanding letters of credit					$ 19,050,000
Interest Rate Swaps [Member]
Debt Instrument [Line Items]
Number of interest rate swaps held | Swap		5
Notional amount of interest rate swap		$ 1,000,000,000
Maturity of interest rate swap					May 14, 2020
Weighted average fixed interest rate		2.45%
Variable rate of interest		0.75%
Variable rate of interest, description					variable rate of interest based upon the greater of 0.75% or the three month BBA LIBOR
Senior Secured Credit Facilities [Member]
Debt Instrument [Line Items]
Percentage of annual excess cash flow used to prepay outstanding loan					50.00%
Percentage of net proceeds from sale of non-ordinary assets					100.00%
Percentage of net proceeds incurrence of debt					100.00%
Mandatory prepayments			$ 6,300,000
First lien secured net leverage ratio					350.00%
Percentage of interest in subsidiary					100.00%
Line of credit facility collateral description					The Senior Secured Credit Facilities are collateralized by first priority or equivalent security interests, subject to certain exceptions, in (i) all the capital stock of, or other equity interests in, SEA and substantially all of SEA’s direct or indirect material wholly-owned domestic subsidiaries and 65% of the capital stock of, or other equity interests in, any “first tier” foreign subsidiaries and (ii) certain tangible and intangible assets of SEA and the Company.
Percentage of capital stock					65.00%
Cash paid for interest				12,904,000	$ 69,408,000	$ 42,521,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Long-term debt				24,351,000
Senior secured revolving					$ 210,000,000
Debt instrument, maturity date description					The New Revolving Credit Facility will mature on the earlier of (a) March 31, 2022 and (b) the 91st day prior to the earlier of (1) the maturity of the Term B-2 Loans with an aggregate principal amount greater than $50,000 and (2) the maturity date of any indebtedness incurred to refinance the Term B-2 loans with an aggregate principal amount greater than $50,000.
Permitted increased commitments under the New Revolving Credit Facility in aggregate principal amount					$ 350,000,000
Interest rate, description					Borrowings of loans in the New Revolving Credit Facility under the Senior Secured Credit Facilities bear interest at a rate equal to an applicable margin over either, at SEA’s option, (a) a base rate determined by reference to the higher of the rate of interest in effect for such day as publicly announced from time to time by Bank of America, N.A. as its “prime rate”, in each case, plus an applicable margin equal to 1.75% and (2) the federal funds rate plus 1/2 of 1% or (b) a LIBOR rate based on the BBA LIBOR rate or the successor thereto if the BBA is no longer making a LIBOR rate available, for the interest period relevant to such borrowing (provided in no event shall such LIBOR rate with respect to the borrowings be less than 0.0% per annum).
Basis point step-down in applicable margin, description					The applicable margin for borrowings under the New Revolving Credit Facility is 1.75%, in the case of base rate loans, and 2.75%, in the case of LIBOR rate loans. The applicable margin for borrowings under the New Revolving Credit Facility are subject to one 25 basis point step-down upon achievement by SEA of certain corporate credit ratings
Basis point step down on applicable margin upon achievement of certain leverage ratio					25.00%
Commitment fees on unused portion of facility					0.50%
Amount available for borrowing					$ 190,950,000
Revolving Credit Facility [Member] | Federal Funds Rate [Member]
Debt Instrument [Line Items]
Applicable margin for Term Loans					0.50%
Revolving Credit Facility [Member] | Base Rate Loan [Member]
Debt Instrument [Line Items]
Applicable margin for Term Loans					1.75%
Revolving Credit Facility [Member] | LIBOR Rate Loan [Member]
Debt Instrument [Line Items]
Applicable margin for Term Loans					2.75%
Revolving Credit Facility [Member] | Minimum [Member] | LIBOR Rate Loan [Member]
Debt Instrument [Line Items]
Debt instrument interest rate effective percentage					0.00%
Restrictive Covenants [Member]
Debt Instrument [Line Items]
Restrictive covenants, restricted payments capacity available					$ 90,000,000
Maximum total net leverage ratio					5.75%
Restrictive Covenants [Member] | Senior Secured Credit Facilities [Member]
Debt Instrument [Line Items]
Restrictive covenants, description					The Senior Secured Credit Facilities permit restricted payments in an aggregate amount per annum equal to the sum of (A) $25,000 plus (B) an amount, if any, equal to (1) if the total net leverage ratio on a pro forma basis after giving effect to the payment of any such restricted payment, is no greater than 3.50 to 1.00, an unlimited amount, (2) if the total net leverage ratio on a pro forma basis after giving effect to the payment of any such restricted payment is no greater than 4.00 to 1.00 and greater than 3.50 to 1.00, the greater of (a) $95,000 and (b) 7.50% of Market Capitalization (as defined in the Senior Secured Credit Facilities), (3) if the total net leverage ratio on a pro forma basis after giving effect to the payment of any such restricted payment is no greater than 4.50 to 1.00 and greater than 4.00 to 1.00, $95,000 and (4) if the total net leverage ratio on a pro forma basis after giving effect to the payment of any such restricted payment is no greater than 5.00 to 1.00 and greater than 4.50 to 1.00, $65,000.
Percentage of Market Capitalization on restricted payment					7.50%
First lien secured net leverage ratio					350.00%
Total net leverage ratio, as calculated					4.93%
Restrictive Covenants [Member] | Senior Secured Credit Facilities [Member] | Maximum [Member]
Debt Instrument [Line Items]
Percentage of annual excess cash flow used to prepay outstanding loan					25.00%
Restricted payment on Senior Secured Credit Facilities, base payment					$ 25,000,000
Restricted payment on Senior Secured Credit Facilities, first payment					95,000,000
Restricted payment on Senior Secured Credit Facilities, second payment					95,000,000
Restricted payment on Senior Secured Credit Facilities, third payment					$ 65,000,000
Total net leverage ratio, one					400.00%
Total net leverage ratio, two					450.00%
Total net leverage ratio, three					500.00%
Restrictive Covenants [Member] | Senior Secured Credit Facilities [Member] | Minimum [Member]
Debt Instrument [Line Items]
Percentage of annual excess cash flow used to prepay outstanding loan					0.00%
Total net leverage ratio, one					350.00%
Total net leverage ratio, two					400.00%
Total net leverage ratio, three					450.00%
Term B-5 Loans [Member]
Debt Instrument [Line Items]
Debt instrument, balance			$ 998,306,000
Discount initially recorded					$ 4,992,000
Debt issuance costs initially recorded					44,000
Write-off of discounts and debt issuance costs					7,987,000
Long-term debt					$ 993,314,000
Long-term debt, maturity date					Mar. 31, 2024
Percent of original principal amount on effective date used to calculate aggregate annual amount which will amortize in equal quarterly installments			1.00%
Interest rate, description					Borrowings of Term B-5 Loans under the Senior Secured Credit Facilities bear interest, at SEA’s option, at a rate equal to an applicable margin over either (a) a base rate determined by reference to the higher of (1) the rate of interest in effect for such day as publicly announced from time to time by Bank of America, N.A. as its “prime rate” and (2) the federal funds rate plus 1/2 of 1% or (b) a LIBOR rate determined by reference to the British Bankers Association (“BBA”) LIBOR Rate, or the successor thereto if the BBA is no longer making a LIBOR rate available for the interest period relevant to such borrowing.
Applicable margin for Term Loans, description					The Term B-5 Loans applicable margin must be adjusted for any Incremental Term Loan (as defined in the Senior Secured Credit Facilities) margin that is more than 50 basis points per annum greater so that the Term B-5 Loans margin is not less than the Incremental Term Loan margin by more than 50 basis points.
Debt instrument interest rate effective percentage					4.33%
Term B-5 Loans [Member] | Federal Funds Rate [Member]
Debt Instrument [Line Items]
Applicable margin for Term Loans					0.50%
Term B-5 Loans [Member] | Base Rate Loan [Member]
Debt Instrument [Line Items]
Applicable margin for Term Loans					2.00%
Term B-5 Loans [Member] | Minimum Margin Adjustment [Member]
Debt Instrument [Line Items]
Adjustment to applicable margin for Term Loans					0.50%
Term B-5 Loans [Member] | LIBOR Rate Loan [Member]
Debt Instrument [Line Items]
Applicable margin for Term Loans					3.00%
Term B-5 Loans [Member] | Minimum [Member] | Base Rate Loan [Member]
Debt Instrument [Line Items]
Debt instrument interest rate effective percentage					1.75%
Term B-5 Loans [Member] | Minimum [Member] | LIBOR Rate Loan [Member]
Debt Instrument [Line Items]
Debt instrument interest rate effective percentage					0.75%
Term B-2 Loans [Member]
Debt Instrument [Line Items]
Debt instrument, balance								$ 1,405,000,000
Repayment of outstanding principal			$ 753,593,000
Long-term debt				$ 1,327,850,000	$ 557,658,000
Long-term debt, maturity date					May 14, 2020
Percent of original principal amount on effective date used to calculate aggregate annual amount which will amortize in equal quarterly installments							1.00%
Interest rate, description					The Term B-2 Loans were initially borrowed in an aggregate principal amount of $1,405,000. Borrowings under the Senior Secured Credit Facilities bear interest, at SEA’s option, at a rate equal to a margin over either (a) a base rate determined by reference to the higher of (1) the rate of interest in effect for such day as publicly announced from time to time by Bank of America, N.A. as its “prime rate” and (2) the federal funds effective rate plus 1/2 of 1% or (b) a LIBOR rate based on the BBA LIBOR rate, or the successor thereto if the BBA is no longer making a LIBOR rate available, for the interest period relevant to such borrowing.
Debt instrument interest rate effective percentage				3.26%	3.58%
Basis point step-down in applicable margin, description					The applicable margin for the Term B-2 Loans (under either a base rate or LIBOR rate) is subject to one 25 basis point step-down upon achievement by SEA of a total net leverage ratio equal to or less than 3.25 to 1.00.
Basis point step down on applicable margin upon achievement of certain leverage ratio					25.00%
Maximum Total Leverage Ratio					325.00%
Term B-2 Loans [Member] | Federal Funds Rate [Member]
Debt Instrument [Line Items]
Applicable margin for Term Loans					0.50%
Term B-2 Loans [Member] | Base Rate Loan [Member]
Debt Instrument [Line Items]
Applicable margin for Term Loans					1.25%
Term B-2 Loans [Member] | LIBOR Rate Loan [Member]
Debt Instrument [Line Items]
Applicable margin for Term Loans					2.25%
Term B-2 Loans [Member] | Minimum [Member] | Base Rate Loan [Member]
Debt Instrument [Line Items]
Debt instrument interest rate effective percentage					1.75%
Term B-2 Loans [Member] | Minimum [Member] | LIBOR Rate Loan [Member]
Debt Instrument [Line Items]
Debt instrument interest rate effective percentage					0.75%
Term B-2 Loans [Member] | Senior Secured Credit Facilities [Member]
Debt Instrument [Line Items]
Mandatory prepayments		$ 2,800,000
Term B-3 Loans [Member]
Debt Instrument [Line Items]
Repayment of outstanding principal			244,713,000
Long-term debt				$ 245,800,000
Debt instrument interest rate effective percentage				4.33%
Mandatory Prepayment of Debt [Member]
Debt Instrument [Line Items]
Write-off of discounts and debt issuance costs	$ 33,000
Voluntary Prepayment of Debt [Member]
Debt Instrument [Line Items]
Write-off of discounts and debt issuance costs					$ 123,000
Term B-2 and Term B-3 Loans [Member] | Senior Secured Credit Facilities [Member]
Debt Instrument [Line Items]
Mandatory prepayments			$ 3,500,000