Commitments and Contingencies - Narrative (Details) - USD ($) $ in Millions	1 Months Ended
	Jun. 30, 2015	Sep. 30, 2017	Aug. 08, 2017	Dec. 31, 2016
Loss Contingencies [Line Items]
Liability associated with legal and regulatory contingencies		$ 58.0		$ 114.0
Unfavorable Regulatory Action
Loss Contingencies [Line Items]
Final order amount company must pay	$ 109.0
HUD Subpoenas
Loss Contingencies [Line Items]
Liability associated with legal and regulatory contingencies			$ 65.0
Other Subpoenas and Investigations
Loss Contingencies [Line Items]
Liability associated with legal and regulatory contingencies			$ 9.5