Long-Term Debt - Additional Information (Detail)				3 Months Ended		12 Months Ended
	Oct. 31, 2018 USD ($)	Jan. 05, 2018 USD ($)	Jan. 03, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2018 USD ($) Swap	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($) Swap	Feb. 28, 2019 USD ($)
Debt Instrument [Line Items]
Long-term debt						$ 1,553,389,000	$ 1,560,046,000
Outstanding letters of credit						$ 21,300,000
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 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%
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.
Percentage of capital stock						65.00%
Cash paid for interest			$ 12,900,000			$ 82,500,000	80,600,000	$ 46,900,000
Terminated Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Senior secured revolving						210,000,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Senior secured revolving						210,000,000
Long-term debt						$ 30,000,000	$ 15,000,000
Long-term debt, maturity date						Oct. 31, 2023
Debt instrument, maturity date description						The New Revolving Credit Facility will mature on October 31, 2023.
Permitted increased commitments under the New Revolving Credit Facility in aggregate principal amount						$ 350,000,000
Interest rate, description						Borrowings of the New Revolving Credit Facility under the Amended Credit Agreement bear interest at a fluctuating rate per annum equal to, at SEA’s option, (i) a base rate equal to the higher of (a) the federal funds rate plus 1⁄2 of 1% and (b) the rate of interest in effect for such day as publicly announced from time to time by JPMorgan Chase Bank, N.A. as its “prime rate”, in each case, plus an applicable margin equal to 1.75%; or (ii) a LIBOR rate based on the British Bankers Association LIBOR Rate (or any successor thereto) for the applicable interest period (provided that in no event shall such LIBOR rate with respect to the New Revolving Credit Facility be less than 0.0% per annum) plus an applicable margin equal to 2.75%.
Debt instrument interest rate effective percentage						5.17%	4.24%
Basis point step-down in applicable margin, description						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, 2018.
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						$ 158,700,000
Revolving Credit Facility [Member] | Federal Funds Rate [Member]
Debt Instrument [Line Items]
Applicable margin for Term Loans						0.50%
Revolving Credit Facility [Member] | Prime Rate [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]
Additional borrowings under revolving credit facility									$ 45,000,000
Revolving Credit Facility [Member] | Senior Secured Credit Facilities [Member]
Debt Instrument [Line Items]
Senior secured revolving	$ 210,000,000
Restrictive Covenants [Member]
Debt Instrument [Line Items]
Restrictive covenants, restricted payments available						$ 180,000,000
Restrictive Covenants [Member] | Senior Secured Credit Facilities [Member]
Debt Instrument [Line Items]
First lien secured net leverage ratio	625.00%
Restrictive covenants, description	The New Revolving Credit Facility requires that the Company comply with a springing maximum first lien secured leverage ratio of 6.25x to be tested as of the last day of any fiscal quarter, solely to the extent that on such date the aggregate amount of funded loans and letters of credit (excluding undrawn letters of credit in an amount not to exceed $30.0 million and cash collateralized letters of credit) under the New Revolving Credit Facility exceeds an amount equal to 35% of the then outstanding commitments under the New Revolving Credit Facility.					The Senior Secured Credit Facilities permit restricted payments in an aggregate amount per annum equal to the sum of (A) $25.0 million plus (B) an amount, if any, equal to (1) if the total 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 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) $95.0 million and (b) 7.50% of Market Capitalization (as defined in the Senior Secured Credit Facilities), (3) if the total 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, $95.0 million and (4) if the total 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, $65.0 million.
Percentage of Market Capitalization on restricted payment						7.50%
First lien secured net leverage ratio						350.00%
Total leverage ratio, as calculated						358.00%
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%
Excludable letters of credit under maximum required first lien secured leverage ratio	$ 30,000,000
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 leverage ratio, one						400.00%
Total leverage ratio, two						450.00%
Total 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%
Minimum percentage of funded loan and letters of credit for covenant to apply	35.00%
Total leverage ratio, one						350.00%
Total leverage ratio, two						400.00%
Total leverage ratio, three						450.00%
Term B-5 Loans [Member]
Debt Instrument [Line Items]
Debt instrument, balance	$ 543,900,000				998,300,000
Discount initially recorded						$ 700,000	$ 5,000,000
Write-off of discounts and debt issuance costs						8,200,000	8,000,000
Long-term debt						$ 1,523,389,000	$ 990,819,000
Long-term debt, maturity date						Mar. 31, 2024
Percent of original principal amount on effective date used to calculate aggregate annual amounts which will amortize in equal quarterly installments						1.015%
Interest rate, description						Borrowings of the Term B-5 Loans under the Amended Credit Agreement bear interest at a fluctuating rate per annum equal to, at SEA’s option, (i) a base rate equal to the higher of (a) the federal funds rate plus 1/2 of 1% and (b) the rate of interest in effect for such day as publicly announced from time to time by JPMorgan Chase Bank, N.A. as its “prime rate” (provided that in no event shall such base rate with respect to the Term B-5 Loans be less than 1.75% per annum), in each case, plus an applicable margin of 2.00% or (ii) a LIBOR rate based on the British Bankers Association LIBOR Rate (or any successor thereto) for the applicable interest period (provided that in no event shall such LIBOR rate with respect to the Term B-5 Loans be less than 0.75% per annum) plus an applicable margin of 3.00%.
Debt instrument interest rate effective percentage						5.52%	4.69%
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] | Prime Rate [Member]
Debt Instrument [Line Items]
Applicable margin for Term Loans						2.00%
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] | Prime Rate [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-5 Loans [Member] | Senior Secured Credit Facilities [Member]
Debt Instrument [Line Items]
Debt instrument, balance	543,900,000
Term B-3 Loans [Member]
Debt Instrument [Line Items]
Repayment of outstanding principal					244,700,000
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]
Repayment of outstanding principal					753,600,000
Long-term debt							$ 554,227,000
Debt instrument interest rate effective percentage							3.94%
Cash paid for interest		$ 5,100,000
Term B-2 Loans [Member] | Senior Secured Credit Facilities [Member]
Debt Instrument [Line Items]
Repayment of outstanding principal	$ 543,900,000
Remainder of mandatory prepayment applied				$ 2,800,000		$ 0		$ 0
Term B-2 and Term B-3 Loans [Member] | Senior Secured Credit Facilities [Member]
Debt Instrument [Line Items]
Mandatory prepayments					$ 3,500,000