Note 23 - Nonconsolidated Variable Interest Entities - VIE Equity Investments and Receivables (Details) - Variable Interest Entity, Not Primary Beneficiary, Aggregated Disclosure [Member] - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Carrying amount, assets	$ 90,001	$ 6,016
Carrying amount, liabilities
Maximum exposure to loss	94,157	7,961
VIE assets	2,592,494	1,439,792
Collateralized Loan Obligations [Member]
Carrying amount, assets	81,329
Carrying amount, liabilities
Maximum exposure to loss	83,581
VIE assets	1,173,722
Private Equity Funds [Member]
Carrying amount, assets	4,705	5,083
Carrying amount, liabilities
Maximum exposure to loss	6,609	7,028
VIE assets	180,435	204,646
Other Equity Interests [Member]
Carrying amount, assets	3,967	933
Carrying amount, liabilities
Maximum exposure to loss	3,967	933
VIE assets	$ 1,238,337	$ 1,235,146