Debt and Borrowing Arrangements - Narrative (Details)	6 Months Ended
Debt and Borrowing Arrangements - Narrative (Details)	Jun. 30, 2018 USD ($)	Jul. 31, 2018 USD ($)	Jul. 01, 2018 USD ($)	Apr. 30, 2018 USD ($)	Apr. 25, 2018 USD ($)	Mar. 29, 2018 USD ($)	Mar. 15, 2018 USD ($)
Committed warehouse facilities \| Barclays Bank PLC
Debt and Borrowing Arrangements
Debt instrument current borrowing capacity					$ 50,000,000
Committed warehouse facilities \| Wells Fargo Bank
Debt and Borrowing Arrangements
Debt instrument current borrowing capacity						$ 50,000,000
Uncommitted warehouse facilities \| Barclays Bank PLC
Debt and Borrowing Arrangements
Debt instrument current borrowing capacity					$ 25,000,000
Variable Funding Notes \| Wells Fargo Bank
Debt and Borrowing Arrangements
Debt instrument current borrowing capacity							$ 25,000,000
Mortgage Warehouse and Servicing Advance Facilities
Debt and Borrowing Arrangements
Debt covenant, net worth threshold amount				$ 334,000,000
Debt covenant, net worth on last day of each fiscal month (up to)	$ 400,000,000
Debt covenant, ratio indebtedness to tangible net worth (no greater than)	4.50
Debt covenant, ratio Of unsecured indebtedness to tangible net worth, cash and cash equivalents adjustment (in excess of)				$ 40,000,000
Debt covenant, maximum unsecured indebtedness to tangible net worth ratio				1.25
Debt covenant, cash and cash equivalents in excess of liability				$ 250,000,000
Debt covenant, capital distribution aggregate amount (up to)				$ 150,000,000
Forecast \| Subsequent Event \| Mortgage Warehouse and Servicing Advance Facilities
Debt and Borrowing Arrangements
Debt covenant, net worth on last day of each fiscal month (up to)		$ 365,000,000
Debt covenant, cash and cash equivalents in excess of liability			$ 225,000,000

PHH CORP 10-Q