Condensed Consolidating Financial Information (Cash Flows) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Cash flows from operating activities
Net Cash Provided by (Used in) Operating Activities	$ 59,638	$ 57,169
Cash flows from investing activities
Capital expenditures	(19,269)	(18,306)
Net Investing Activity with Affiliates	0byd_NetInvestingActivitywithAffiliates	0byd_NetInvestingActivitywithAffiliates
Other investing activities	2,316	1,112
Net cash used in investing activities	(16,953)	(17,194)
Cash flows from financing activities
Borrowings under bank credit facility	295,100byd_ProceedsFromCombinedLinesOfCredit	379,700byd_ProceedsFromCombinedLinesOfCredit
Payments under bank credit facility	(354,300)byd_RepaymentsOfCombinedLinesOfCredit	(434,200)byd_RepaymentsOfCombinedLinesOfCredit
Debt financing costs	0us-gaap_PaymentsOfDebtIssuanceCosts	(71)us-gaap_PaymentsOfDebtIssuanceCosts
Payments on long-term debt	(2)us-gaap_RepaymentsOfNotesPayable	(952)us-gaap_RepaymentsOfNotesPayable
Payments on retirements of long-term debt	(2)byd_PaymentsOnRetirementsOfLongTermDebt	(952)byd_PaymentsOnRetirementsOfLongTermDebt
Proceeds from Contributions from Affiliates	0byd_NetFinancingActivitywithAffiliates	0byd_NetFinancingActivitywithAffiliates
Stock options exercised	4,419	757
Restricted Stock, Value, Shares Issued Net of Tax Withholdings	0	200
Performance Stock, Value, Shares Issued Net of Tax Withholdings	(2,446)	0
Proceeds from (Payments for) Combined Other Financing Activities		31
Net cash used in financing activities	(57,229)	(54,935)
Cash and cash equivalents, beginning of period	145,341	177,838
Cash and cash equivalents, end of period	(130,797)	(162,878)
Cash and Cash Equivalents, Period Increase (Decrease)	(14,544)	(14,960)
Parent
Cash flows from operating activities
Net Cash Provided by (Used in) Operating Activities	(26,888)	(20,187)
Cash flows from investing activities
Capital expenditures	(6,152)	(4,683)
Net Investing Activity with Affiliates	0	0
Other investing activities	0	660
Net cash used in investing activities	(6,152)	(4,023)
Cash flows from financing activities
Borrowings under bank credit facility	203,700	188,500
Payments under bank credit facility	(245,675)	(224,275)
Debt financing costs		(71)
Payments on long-term debt	0	0
Proceeds from Contributions from Affiliates	73,815	59,468
Stock options exercised	4,419	757
Restricted Stock, Value, Shares Issued Net of Tax Withholdings		200
Performance Stock, Value, Shares Issued Net of Tax Withholdings	(2,446)
Proceeds from (Payments for) Combined Other Financing Activities		31
Net cash used in financing activities	33,813	24,210
Cash and cash equivalents, beginning of period	2	0
Cash and cash equivalents, end of period	(775)	0
Cash and Cash Equivalents, Period Increase (Decrease)	773	0
Guarantor Subsidiaries
Cash flows from operating activities
Net Cash Provided by (Used in) Operating Activities	75,990	68,688
Cash flows from investing activities
Capital expenditures	(6,006)	(6,298)
Net Investing Activity with Affiliates	(83,331)	(65,848)
Other investing activities	0	0
Net cash used in investing activities	(89,337)	(72,146)
Cash flows from financing activities
Borrowings under bank credit facility	0	0
Payments under bank credit facility	0	0
Debt financing costs		0
Payments on long-term debt	0	0
Proceeds from Contributions from Affiliates	0	0
Stock options exercised	0	0
Restricted Stock, Value, Shares Issued Net of Tax Withholdings		0
Performance Stock, Value, Shares Issued Net of Tax Withholdings	0
Proceeds from (Payments for) Combined Other Financing Activities		0
Net cash used in financing activities	0	0
Cash and cash equivalents, beginning of period	111,452	106,445
Cash and cash equivalents, end of period	(98,105)	(102,987)
Cash and Cash Equivalents, Period Increase (Decrease)	(13,347)	(3,458)
Non-Guarantor Subsidiaries (100% Owned)
Cash flows from operating activities
Net Cash Provided by (Used in) Operating Activities	5,730	14,670
Cash flows from investing activities
Capital expenditures	(7,111)	(5,516)
Net Investing Activity with Affiliates	0	3,278
Other investing activities	2,316	1
Net cash used in investing activities	(4,795)	(2,237)
Cash flows from financing activities
Borrowings under bank credit facility	91,400	75,000
Payments under bank credit facility	(108,625)	(90,525)
Debt financing costs		0
Payments on long-term debt	(2)	(2)
Proceeds from Contributions from Affiliates	14,322	0
Stock options exercised	0	0
Restricted Stock, Value, Shares Issued Net of Tax Withholdings		0
Performance Stock, Value, Shares Issued Net of Tax Withholdings	0
Proceeds from (Payments for) Combined Other Financing Activities		0
Net cash used in financing activities	(2,905)	(15,527)
Cash and cash equivalents, beginning of period	33,668	33,766
Cash and cash equivalents, end of period	(31,698)	(30,672)
Cash and Cash Equivalents, Period Increase (Decrease)	(1,970)	(3,094)
Non-Guarantor Subsidiaries (Not 100% Owned)
Cash flows from operating activities
Net Cash Provided by (Used in) Operating Activities	(41)	(2,942)
Cash flows from investing activities
Capital expenditures	0	(1,809)
Net Investing Activity with Affiliates	0	42
Other investing activities	0	451
Net cash used in investing activities	0	(1,316)
Cash flows from financing activities
Borrowings under bank credit facility	0	116,200
Payments under bank credit facility	0	(119,400)
Debt financing costs		0
Payments on long-term debt	0	(950)
Proceeds from Contributions from Affiliates	41	0
Stock options exercised	0	0
Restricted Stock, Value, Shares Issued Net of Tax Withholdings		0
Performance Stock, Value, Shares Issued Net of Tax Withholdings	0
Proceeds from (Payments for) Combined Other Financing Activities		0
Net cash used in financing activities	41	(4,150)
Cash and cash equivalents, beginning of period	219	37,627
Cash and cash equivalents, end of period	(219)	(29,219)
Cash and Cash Equivalents, Period Increase (Decrease)	0	(8,408)
Eliminations
Cash flows from operating activities
Net Cash Provided by (Used in) Operating Activities	4,847	(3,060)
Cash flows from investing activities
Capital expenditures	0	0
Net Investing Activity with Affiliates	83,331	62,528
Other investing activities	0	0
Net cash used in investing activities	83,331	62,528
Cash flows from financing activities
Borrowings under bank credit facility	0	0
Payments under bank credit facility	0	0
Debt financing costs		0
Payments on long-term debt	0	0
Proceeds from Contributions from Affiliates	(88,178)	(59,468)
Stock options exercised	0	0
Restricted Stock, Value, Shares Issued Net of Tax Withholdings		0
Performance Stock, Value, Shares Issued Net of Tax Withholdings	0
Proceeds from (Payments for) Combined Other Financing Activities		0
Net cash used in financing activities	(88,178)	(59,468)
Cash and cash equivalents, beginning of period	0	0
Cash and cash equivalents, end of period	0	0
Cash and Cash Equivalents, Period Increase (Decrease)	$ 0	$ 0

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