Segments - Geographic Concentration (Details)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Geographic concentration
Percentage of unpaid principal balance of the loans serviced for others	100.00%	100.00%	100.00%
California
Geographic concentration
Percentage of unpaid principal balance of the loans serviced for others	16.10%	14.90%	17.10%
Florida
Geographic concentration
Percentage of unpaid principal balance of the loans serviced for others	8.40%	8.50%	8.20%
Texas
Geographic concentration
Percentage of unpaid principal balance of the loans serviced for others	7.90%	7.50%	7.10%
Maryland
Geographic concentration
Percentage of unpaid principal balance of the loans serviced for others	3.60%	6.10%	8.10%
Virginia
Geographic concentration
Percentage of unpaid principal balance of the loans serviced for others	4.70%	5.20%	5.70%
All other states
Geographic concentration
Percentage of unpaid principal balance of the loans serviced for others	59.30%	57.80%	53.80%
Maximum
Geographic concentration
Threshold percentage, unpaid principal balance and related servicing revenues by geographical area	5.00%