Note 15 - Stockholders' Equity - Preferred Stock Redeemed (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Redemption Charges		$ 11,369	$ (0)	$ 11,369	$ (0)
Series I Preferred Stock [Member]
Depositary Shares Redeemed (in shares)				7,000,000
Redemption Price (in dollars per share)		$ 25.00		$ 25.00
Redemption Amount		$ 175,000		$ 175,000
Redemption Charges	[1]			$ 5,500
Series K Preferred Stock [Member]
Depositary Shares Redeemed (in shares)				7,000,000
Redemption Price (in dollars per share)		$ 25.00		$ 25.00
Redemption Amount		$ 175,000		$ 175,000
Redemption Charges	[1]			$ 5,900

[1] Redemption charges resulting from the difference between the redemption amount and the carrying amount of the respective preferred stock class on the Company's Condensed Consolidated Balance Sheets are accounted for in accordance with the FASB's guidance on Distinguishing Liabilities from Equity. These charges were subtracted from net income attributable to the Company to arrive at net income available to the Company's common shareholders and used in the calculation of earnings per share.