Debt (Details) | 3 Months Ended | | |
Mar. 31, 2018USD ($)credit_facilityasset-backed_warehouse_facilitiy | Mar. 20, 2018USD ($) | Dec. 31, 2017USD ($) |
Debt Instrument [Line Items] | | | |
Debt outstanding on facilities with fixed interest rates | $ 4,638,800,000 | | |
Debt Instrument Interest Rate During Period Fixed Rate Debt | 4.27% | | |
Long Term Debt, Percentage Bearing Fixed Interest Rate Remaining Term | 4 years 3 months 18 days | | |
Debt outstanding on facilities with interest rates based on floating rate indices | $ 2,381,800,000 | | |
Debt Instrument Interest Rate During Period Variable Rate Debt | 3.93% | | |
Long Term Debt, Percentage Bearing Variable Interest Rate Remaining Term | 2 years 8 months 12 days | | |
Percentage of Debt Hedged by Interest Rate Derivatives | 83.60% | | |
Debt Instrument Interest Rate During Period Fixed Rate and Interest Swap Rate Debt | 4.19% | | |
Hedged Portion of Debt Average Remaining Maturity | 4 years 3 months 18 days | | |
Debt Instrument, Interest Rate During Period | 4.16% | | |
Number Of Asset-backed Warehouse Facilities | asset-backed_warehouse_facilitiy | 2 | | |
Institutional Notes [Domain] | | | |
Debt Instrument [Line Items] | | | |
Debt and Capital Lease Obligations | $ 2,358,200,000 | | $ 2,381,000,000 |
Debt Instrument, Interest Rate, Effective Percentage | 4.78% | | |
Asset-backed securitization term notes | | | |
Debt Instrument [Line Items] | | | |
Debt and Capital Lease Obligations | $ 2,741,690,000 | | 2,378,470,000 |
Debt Instrument, Interest Rate, Effective Percentage | 3.76% | 3.99% | |
Debt Instrument, Face Amount | | $ 450,000,000 | |
Term Notes [Member] | | | |
Debt Instrument [Line Items] | | | |
Debt Instrument, Interest Rate, Effective Percentage | 3.93% | | |
Asset Backed Warehouse Facility [Member] | | | |
Debt Instrument [Line Items] | | | |
Debt and Capital Lease Obligations | $ 130,000,000 | | 110,000,000 |
Debt Instrument, Advance Rate Used in Calculating Borrowing Capacity | 80.00% | | |
Debt Instrument, Interest Rate, Effective Percentage | 3.67% | | |
Maximum borrowing capacity | $ 600 | | |
Revolving credit facilities | | | |
Debt Instrument [Line Items] | | | |
Debt and Capital Lease Obligations | $ 40,000,000 | | 305,000,000 |
Debt Instrument, Advance Rate Used in Calculating Borrowing Capacity | 83.00% | | |
Debt Instrument, Interest Rate, Effective Percentage | 4.62% | | |
Maximum borrowing capacity | $ 1,075,000,000 | | |
Number of Credit Facilities | credit_facility | 2 | | |
Capital lease obligations | | | |
Debt Instrument [Line Items] | | | |
Debt and Capital Lease Obligations | $ 96,235,000 | | $ 103,409,000 |
Interest Rate Swap [Member] | | | |
Debt Instrument [Line Items] | | | |
Net notional amount | $ 1,233,000,000 | | |
Net Notional Amount of Interest Rate During Period | 1.87% | | |
Weighted Average Remaining Term | 4 years 4 months 24 days | | |
Asset-backed Warehouse Facility A [Member] | Asset Backed Warehouse Facility [Member] | | | |
Debt Instrument [Line Items] | | | |
Maximum borrowing capacity | $ 200,000,000 | | |
Asset-backed Warehouse Facility B [Member] | Asset Backed Warehouse Facility [Member] | | | |
Debt Instrument [Line Items] | | | |
Maximum borrowing capacity | $ 400,000,000 | | |
Minimum [Member] | | | |
Debt Instrument [Line Items] | | | |
Capital Lease Period Over Which Interest Expense Recognized Preceding Early Purchase Option | 3 years | | |
Minimum [Member] | Institutional Notes [Domain] | | | |
Debt Instrument [Line Items] | | | |
Debt Instrument, Term | 7 years | | |
Debt Instrument, Advance Rate Used in Calculating Borrowing Capacity | 83.00% | | |
Minimum [Member] | Asset-backed securitization term notes | | | |
Debt Instrument [Line Items] | | | |
Debt Instrument, Advance Rate Used in Calculating Borrowing Capacity | 77.00% | | |
Minimum [Member] | Term Notes [Member] | | | |
Debt Instrument [Line Items] | | | |
Debt Instrument, Advance Rate Used in Calculating Borrowing Capacity | 80.00% | | |
Minimum [Member] | Asset Backed Warehouse Facility [Member] | | | |
Debt Instrument [Line Items] | | | |
Bank Account Maintenance Required Amount Balance, Interest Expense | 3 months | | |
Minimum [Member] | Capital lease obligations | | | |
Debt Instrument [Line Items] | | | |
Debt Instrument, Interest Rate, Effective Percentage | 3.26% | | |
Maximum [Member] | | | |
Debt Instrument [Line Items] | | | |
Capital Lease Period Over Which Interest Expense Recognized Preceding Early Purchase Option | 10 years | | |
Maximum [Member] | Institutional Notes [Domain] | | | |
Debt Instrument [Line Items] | | | |
Debt Instrument, Term | 12 years | | |
Debt Instrument, Advance Rate Used in Calculating Borrowing Capacity | 85.00% | | |
Maximum [Member] | Asset-backed securitization term notes | | | |
Debt Instrument [Line Items] | | | |
Debt Instrument, Advance Rate Used in Calculating Borrowing Capacity | 87.00% | | |
Maximum [Member] | Term Notes [Member] | | | |
Debt Instrument [Line Items] | | | |
Debt Instrument, Advance Rate Used in Calculating Borrowing Capacity | 83.00% | | |
Maximum [Member] | Asset Backed Warehouse Facility [Member] | | | |
Debt Instrument [Line Items] | | | |
Bank Account Maintenance Required Amount Balance, Interest Expense | 5 months | | |
Maximum [Member] | Capital lease obligations | | | |
Debt Instrument [Line Items] | | | |
Debt Instrument, Interest Rate, Effective Percentage | 4.93% | | |
Pre-Conversion [Member] | London Interbank Offered Rate (LIBOR) [Member] | Asset-backed Warehouse Facility A [Member] | Asset Backed Warehouse Facility [Member] | | | |
Debt Instrument [Line Items] | | | |
Debt Instrument, Basis Spread on Variable Rate | 2.25% | | |
Pre-Conversion [Member] | London Interbank Offered Rate (LIBOR) [Member] | Asset-backed Warehouse Facility B [Member] | Asset Backed Warehouse Facility [Member] | | | |
Debt Instrument [Line Items] | | | |
Debt Instrument, Basis Spread on Variable Rate | 1.85% | | |
Post-Conversion [Member] | London Interbank Offered Rate (LIBOR) [Member] | Asset-backed Warehouse Facility A [Member] | Asset Backed Warehouse Facility [Member] | | | |
Debt Instrument [Line Items] | | | |
Debt Instrument, Basis Spread on Variable Rate | 3.25% | | |
Post-Conversion [Member] | London Interbank Offered Rate (LIBOR) [Member] | Asset-backed Warehouse Facility B [Member] | Asset Backed Warehouse Facility [Member] | | | |
Debt Instrument [Line Items] | | | |
Debt Instrument, Basis Spread on Variable Rate | 2.85% | | |
Interest Rate Swap [Member] | | | |
Debt Instrument [Line Items] | | | |
Debt Instrument Interest Rate During Period Variable Rate Debt | 3.95% | | |
Debt and Capital Lease Obligations | $ 5,871,800,000 | | |