Derivatives - Offsetting of Derivative Instruments (Detail) - USD ($)	Mar. 31, 2024	Dec. 31, 2023
Offsetting Assets [Line Items]
Gross amounts, assets	$ 84,438,000	$ 79,325,000
Gross amounts offset, assets	(79,449,000)	(75,718,000)
Net amounts presented in the statements of financial condition, assets	4,989,000	3,607,000
Gross amounts, liabilities	82,534,000	81,474,000
Gross amounts offset, liabilities	(79,449,000)	(75,718,000)
Net amounts presented in the statements of financial condition, liabilities	3,085,000	5,756,000
Additional balance in gross amounts not offset	0	0
FX swaps
Offsetting Assets [Line Items]
Gross amounts, assets	4,663,000	3,467,000
Gross amounts offset, assets	(596,000)	(793,000)
Net amounts presented in the statements of financial condition, assets	4,067,000	2,674,000
Gross amounts, liabilities	3,004,000	5,912,000
Gross amounts offset, liabilities	(596,000)	(793,000)
Net amounts presented in the statements of financial condition, liabilities	2,408,000	5,119,000
Interest rate swaps
Offsetting Assets [Line Items]
Gross amounts, assets	9,359,000	12,310,000
Gross amounts offset, assets	(9,268,000)	(12,182,000)
Net amounts presented in the statements of financial condition, assets	91,000	128,000
Gross amounts, liabilities	9,268,000	12,182,000
Gross amounts offset, liabilities	(9,268,000)	(12,182,000)
Net amounts presented in the statements of financial condition, liabilities	0	0
Forwards
Offsetting Assets [Line Items]
Gross amounts, assets	861,000	855,000
Gross amounts offset, assets	(30,000)	(50,000)
Net amounts presented in the statements of financial condition, assets	831,000	805,000
Gross amounts, liabilities	646,000	659,000
Gross amounts offset, liabilities	(30,000)	(50,000)
Net amounts presented in the statements of financial condition, liabilities	616,000	609,000
Futures
Offsetting Assets [Line Items]
Gross amounts, assets	69,555,000	62,693,000
Gross amounts offset, assets	(69,555,000)	(62,693,000)
Net amounts presented in the statements of financial condition, assets	0	0
Gross amounts, liabilities	69,616,000	62,721,000
Gross amounts offset, liabilities	(69,555,000)	(62,693,000)
Net amounts presented in the statements of financial condition, liabilities	$ 61,000	$ 28,000