Partnership's Borrowings Through Consolidated CLO Vehicles (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Weighted Average Interest Rate		2.54%	2.92%
Liabilities of Consolidated CLO Vehicles
Debt Instrument [Line Items]
Borrowing Outstanding		$ 11,583,607	$ 5,506,976
Liabilities of Consolidated CLO Vehicles | Senior Secured Notes
Debt Instrument [Line Items]
Borrowing Outstanding		$ 10,689,240	$ 5,124,241
Weighted Average Interest Rate		2.35%	2.17%
Weighted Average Remaining Maturity in Years		4 years 1 month 6 days	5 years 4 months 24 days
Liabilities of Consolidated CLO Vehicles | Subordinated Notes
Debt Instrument [Line Items]
Borrowing Outstanding		$ 894,367	$ 382,735
Weighted Average Interest Rate	[1]

[1] The Subordinated Notes do not have contractual interest rates but instead receive distributions from the excess cash flows of the CLO vehicles.