Fair Value Measurement - Fair Value of Assets (Liabilities) Not Measured at Fair Value In Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Level 1 | Fixed-Rate Long-Term Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt, fair value	$ 0	$ 0
Level 1 | Perfect Home Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value	0	0
Level 2 | Fixed-Rate Long-Term Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt, fair value	(184,249)	(273,476)
Level 2 | Perfect Home Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value	0	0
Level 3 | Fixed-Rate Long-Term Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt, fair value	0	0
Level 3 | Perfect Home Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value	$ 0	$ 20,385