Debt (Narrative) (Details)					12 Months Ended
		Mar. 30, 2015 USD ($)	Feb. 21, 2014 USD ($)	Jan. 22, 2014 USD ($)	Dec. 31, 2015 USD ($) facility	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Sep. 30, 2015
Debt Instrument [Line Items]
Maximum hedging reserve					$ 1,000,000
Debt financing amount					$ 2,086,300,000	$ 1,752,500,000
Percentage of collections on contributed loans					6.00%
Monthly servicing fee per financing					6.00%
Repayments of senior notes					$ 0	350,000,000	$ 0
Loss on extinguishment of debt					0	(21,800,000)	0
Debt covenants					1
Proceeds from issuance of senior notes					$ 248,200,000	300,000,000	$ 0
Revolving Secured Line Of Credit [Member]
Debt Instrument [Line Items]
Debt maturity date					Jun. 22, 2018
Line of credit facility					$ 310,000,000
Percentage of net book value of loans					80.00%
Debt financing amount					$ 57,700,000	$ 119,500,000
Warehouse Facilities [Member]
Debt Instrument [Line Items]
Percentage of net book value of loans					80.00%
Number of warehouse facilities | facility					4
Debt financing amount					$ 650,000,000
Warehouse Facility II [Member]
Debt Instrument [Line Items]
Debt maturity date	[1],[2]				Jul. 18, 2017
Debt financing amount	[1],[3]				$ 400,000,000
Interest rate					2.24%	2.16%
Warehouse Facility IV [Member]
Debt Instrument [Line Items]
Debt maturity date	[1],[2]				Apr. 30, 2018
Debt financing amount	[1],[3]				$ 75,000,000
Interest rate					2.42%	2.17%
Warehouse Facility V [Member]
Debt Instrument [Line Items]
Debt maturity date	[1],[4]				Sep. 10, 2017
Debt financing amount	[1],[3]				$ 100,000,000
Interest rate					1.84%	1.77%
Warehouse Facility VI [Member]
Debt Instrument [Line Items]
Debt maturity date	[1],[2]				Sep. 30, 2018
Debt financing amount	[1]				$ 75,000,000
Interest rate					2.24%	0.00%
2017 Senior Notes [Member]
Debt Instrument [Line Items]
Senior notes stated interest rate								9.125%
Debt Instrument, Repurchase Date			Feb. 21, 2014
Repayments of senior notes			$ 350,000,000
Loss on extinguishment of debt			$ 21,800,000
2021 Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Issuance Date				Jan. 22, 2014
Debt maturity date				Feb. 15, 2021	Feb. 15, 2021
Debt financing amount				$ 300,000,000	$ 300,000,000
Senior notes stated interest rate				6.125%
Interest rate					6.125%	6.125%
2023 Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Issuance Date		Mar. 30, 2015
Debt maturity date		Mar. 15, 2023			Mar. 15, 2023
Debt financing amount		$ 250,000,000			$ 250,000,000
Senior notes stated interest rate		7.375%
Redemption price, percentage of principal amount redeemed		99.266%
Proceeds from issuance of senior notes		$ 248,200,000
Interest rate		7.50%			7.375%	0.00%
London Interbank Offered Rate (LIBOR) [Member] | Revolving Secured Line Of Credit [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate					1.875%
London Interbank Offered Rate (LIBOR) [Member] | Warehouse Facility II [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate					2.00%
London Interbank Offered Rate (LIBOR) [Member] | Warehouse Facility IV [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate					2.00%
London Interbank Offered Rate (LIBOR) [Member] | Warehouse Facility V [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate					1.60%
London Interbank Offered Rate (LIBOR) [Member] | Warehouse Facility VI [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate					2.00%
Prime Rate [Member] | Revolving Secured Line Of Credit [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate					0.875%

[1] Financing made available only to a specified subsidiary of the Company.

[2] Represents the revolving maturity date. The outstanding balance will amortize after the maturity date based on the cash flows of the pledged assets.

[3] Interest rate cap agreements are in place to limit the exposure to increasing interest rates.

[4] Represents the revolving maturity date. The outstanding balance will amortize after the revolving maturity date and any amounts remaining on September 10, 2019 will be due.