Long-Term Debt - Additional Information (Detail)					1 Months Ended	3 Months Ended		12 Months Ended
	Feb. 28, 2018 USD ($)	Jan. 05, 2018 USD ($)	Mar. 30, 2017 USD ($)	Jan. 03, 2017 USD ($)	Dec. 31, 2015 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($) Swap	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2016 USD ($) Swap	May 14, 2013	Dec. 01, 2009 USD ($)
Debt Instrument [Line Items]
Long-term debt								$ 1,560,046,000	$ 1,598,001,000
Repayment of revolving credit facility								105,000,000	100,000,000	$ 45,000,000
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
Number of interest rate swaps matured | Swap											4
Interest Rate Swaps [Member] | Combined Interest Rate Cash Flow Hedges On Three Swaps [Member]
Debt Instrument [Line Items]
Notional amount of interest rate swap											$ 1,000,000,000
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
Number of interest rate derivatives held with combined notional amount | Swap											3
Interest Rate Swaps [Member] | Fourth Traditional Swap [Member]
Debt Instrument [Line Items]
Notional amount of interest rate swap											$ 250,000,000
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
Fixed interest rate											0.901%
Maximum [Member] | Interest Rate Swaps [Member] | Combined Interest Rate Cash Flow Hedges On Three Swaps [Member]
Debt Instrument [Line Items]
Weighted average fixed interest rate											1.051%
Minimum [Member] | Interest Rate Swaps [Member] | Combined Interest Rate Cash Flow Hedges On Three Swaps [Member]
Debt Instrument [Line Items]
Weighted average fixed interest rate											1.049%
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Unamortized debt issuance costs and discounts								$ 2,524,000	1,324,000
Long-term debt								15,000,000	$ 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 a 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” 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).
Debt instrument interest rate effective percentage								4.24%	3.46%
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 which the Company did not achieve as of December 31, 2017.
Basis point step down on applicable margin upon achievement of certain leverage ratio								0.25%
Commitment fees on unused portion of facility								0.50%
Amount available for borrowing								$ 175,950,000
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%
Revolving Credit Facility [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Debt instrument, balance	$ 40,000,000
Repayment of revolving credit facility	$ 5,000,000
Restrictive Covenants [Member]
Debt Instrument [Line Items]
Restrictive covenants, restricted payments available								$ 25,000,000
Maximum total net leverage ratio								575.00%
Senior Notes [Member]
Debt Instrument [Line Items]
Repayment of outstanding principal					$ 260,000,000
Write-off of discounts and debt issuance costs										6,048,000
Debt redemption premium										14,300,000
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, substantially all of SEA’s direct or indirect material 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. Certain financial, affirmative and negative covenants, including a maximum total net leverage ratio, minimum interest coverage ratio and maximum capital expenditures are included in the Senior Secured Credit Facilities.
Percentage of capital stock								65.00%
Cash paid for interest				$ 12,904,000				$ 80,570,000	$ 46,919,000	63,726,000
Senior Secured Credit Facilities [Member] | Restrictive Covenants [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								508.00%
Reduction in total net leverage ratio								500.00%
Senior Secured Credit Facilities [Member] | Restrictive Covenants [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%
Senior Secured Credit Facilities [Member] | Restrictive Covenants [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%
April 7, 2015 | Senior Notes [Member]
Debt Instrument [Line Items]
Redemption price for Senior Notes Percentage					105.50%
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
Unamortized debt issuance costs and discounts								11,904,000
Long-term debt								$ 990,819,000
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								4.69%
Term B-5 Loans [Member] | Federal Funds Rate [Member]
Debt Instrument [Line Items]
Applicable margin for Term Loans								10.50%
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-3 Loans [Member]
Debt Instrument [Line Items]
Debt instrument, balance					$ 280,000,000					280,000,000
Repayment of outstanding principal							$ 244,713,000
Unamortized debt issuance costs and discounts									2,638,000
Long-term debt									$ 245,800,000
Debt instrument interest rate effective percentage									4.33%
Term B-3 Loans [Member] | Senior Secured Credit Facilities [Member]
Debt Instrument [Line Items]
Mandatory prepayments									$ 0	0
Term B-2 Loans [Member]
Debt Instrument [Line Items]
Debt instrument, balance													$ 1,405,000,000
Repayment of outstanding principal							753,593,000
Unamortized debt issuance costs and discounts								$ 3,302,000	11,257,000
Long-term debt								$ 554,227,000	$ 1,327,850,000
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 of Term B-2 Loans 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 determined by reference to 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								3.94%	3.26%
Basis point step-down in applicable margin, description								The applicable margin for the Term B-2 Loans is 1.25%, in the case of base rate loans, and 2.25%, in the case of LIBOR rate loans, subject to a base rate floor of 1.75% and a LIBOR floor of 0.75%. 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%
Debt instrument interest rate effective percentage								1.75%
Term B-2 Loans [Member] | LIBOR Rate Loan [Member]
Debt Instrument [Line Items]
Applicable margin for Term Loans								2.25%
Debt instrument interest rate effective percentage								0.75%
Term B-2 Loans [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Cash paid for interest		$ 5,050,000
Term B-2 Loans [Member] | Senior Secured Credit Facilities [Member]
Debt Instrument [Line Items]
Mandatory prepayments						$ 2,800,000			$ 0	$ 0
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