Combined Guarantor Subsidiaries - Revenues - Narrative (Details)	9 Months Ended
	Sep. 30, 2019 extension_option
Condensed Financial Statements, Captions [Line Items]
Period between increases in fixed rate of arrangements	5 years
Number of extension options available (one or more)	1
Period of extension option (50 or more years)	50 years
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Period between increases in fixed rate of arrangements	5 years
Number of extension options available (one or more)	1
Period of extension option (50 or more years)	50 years