Guarantees of Registered Securities - Narrative (Details) - RCI (Issuer) [Member]	3 Months Ended
	Jun. 30, 2017
Condensed Financial Statements, Captions [Line Items]
Subsidiary ownership percentage by parent	100.00%
Unsecured Debt [Member] | 7.375% Senior Note Payable Due June 2025 [Member]
Condensed Financial Statements, Captions [Line Items]
Stated interest rate percentage	7.375%
Unsecured Debt [Member] | 5.4% Senior Notes due 2042 [Member]
Condensed Financial Statements, Captions [Line Items]
Stated interest rate percentage	5.40%
Unsecured Debt [Member] | 5.85% Senior Notes, due January 2044 [Member]
Condensed Financial Statements, Captions [Line Items]
Stated interest rate percentage	5.85%