Shareholders' Equity (Details Narrative) - USD ($) $ / shares in Units, $ in Thousands						1 Months Ended		3 Months Ended		5 Months Ended
	Apr. 02, 2020	Mar. 16, 2020	Mar. 13, 2020	Jan. 15, 2020	Oct. 21, 2019	May 07, 2020	Mar. 31, 2020	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020
Proceed from dividend reinvestment and stock purchase plan (DRIP)								$ 904	$ 1,800
New shares issued under drip, value								1,601	10,671
Stock repurchased during period, value								1,604
Proceeds from issuance of offering								63,132	0
Preferred Stock At-The-Market Sales Program [Member]
Number of aggregate sales price								$ 19,500
Number shares issued and sold								2,600,000
Sale of stock price per share							$ 25.06	$ 25.06		$ 25.06
Gross proceeds from issuance of stock								$ 64,100
Proceeds from issuance of offering								63,100
Preferred Stock At-The-Market Sales Program [Member] | Maximum [Member]
Number of aggregate sales price					$ 100,000
Common Stock [Member]
Proceed from dividend reinvestment and stock purchase plan (DRIP)								904
New shares issued under drip, value								$ 1,600
New shares issued under drip								133,000
Stock repurchased during period, value							$ 1,600
Stock repurchased during period, shares							152,000
Weighted average price per shares							$ 10.57	$ 10.57		$ 10.57
Common Stock [Member] | Common Stock Repurchase Program [Member]
Purchase of common stock authorized				$ 25,000
8.0% Series B Cumulative Redeemable Preferred Stock [Member] | Series B Preferred Stock Repurchase Program [Member]
Stock repurchased during period, value							$ 12
Stock repurchased during period, shares							531
Purchase of preferred stock authorized, value			$ 5,000
6.75% Series C Cumulative Redeemable Preferred Stock [Member]
Dividends paid		$ 4,100
Dividend declared per share, paid		$ 0.421875
Record date of dividend		Feb. 18, 2020
Annual rate on dividend per share payable quarterly		$ 1.6875
Dividend payable date, description		December 1, 2019 through February 29, 2020
Cumulative redeemable preferred stock percentage		6.75%
Preferred stock, liquidation preference per share		$ 25.00
6.375% Series D Cumulative Redeemable Preferred Stock [Member]
Dividends paid		$ 2,100
Dividend declared per share, paid		$ 0.3984375
Record date of dividend		Feb. 18, 2020
Annual rate on dividend per share payable quarterly		$ 1.59375
Dividend payable date, description		December 1, 2019 through February 29, 2020
Cumulative redeemable preferred stock percentage		6.375%
Preferred stock, liquidation preference per share		$ 25.00
Subsequent Event [Member] | Common Stock [Member]
Stock repurchased during period, value						$ 199
Stock repurchased during period, shares						20,000
Weighted average price per shares						$ 9.96
Subsequent Event [Member] | 6.75% Series C Cumulative Redeemable Preferred Stock [Member]
Record date of dividend	May 15, 2020
Annual rate on dividend per share payable quarterly	$ 0.421875
Dividend paid date	Jun. 15, 2020
Dividend payable date, description	March 1, 2020 through May 31, 2020
Subsequent Event [Member] | 6.375% Series D Cumulative Redeemable Preferred Stock [Member]
Record date of dividend	May 15, 2020
Annual rate on dividend per share payable quarterly	$ 0.3984375
Dividend paid date	Jun. 15, 2020
Dividend payable date, description	March 1, 2020 through May 31, 2020
Cumulative redeemable preferred stock percentage	6.375%
Common Stock [Member]
Dividends paid		$ 7,400
Dividend declared per share, paid		$ 0.18
Record date of dividend		Feb. 18, 2020
Proceed from dividend reinvestment and stock purchase plan (DRIP)		$ 904
New shares issued under drip, value								$ 13	$ 84
New shares issued under drip								133,000	837,000
Stock repurchased during period, value								$ 15
Stock repurchased during period, shares								(152,000)
Common Stock [Member] | Subsequent Event [Member]
Record date of dividend	May 15, 2020
Annual rate on dividend per share payable quarterly	$ 0.18
Dividend paid date	Jun. 15, 2020
8.0% Series B Cumulative Redeemable Preferred Stock [Member]
Dividends paid		$ 1,900
Dividend declared per share, paid		$ 0.50
Record date of dividend		Feb. 18, 2020
Annual rate on dividend per share payable quarterly		$ 2.00
Dividend payable date, description		December 1, 2019 through February 29, 2020
Cumulative redeemable preferred stock percentage		8.00%
Preferred stock, liquidation preference per share		$ 25.00
8.0% Series B Cumulative Redeemable Preferred Stock [Member] | Subsequent Event [Member]
Dividend declared per share, paid	$ 0.50
Record date of dividend	May 15, 2020
Dividend paid date	Jun. 15, 2020
Dividend payable date, description	The period from March 1, 2020 through May 31, 2020 to be paid on June 15, 2020 to Series B Preferred Stock shareholders of record as of the close of business on May 15, 2020.
Series D Preferred Stock [Member]
New shares issued under drip, value								$ 0	$ 0
Stock repurchased during period, value								$ 0
Series D Preferred Stock [Member] | Preferred Stock At-The-Market Sales Program [Member]
Number shares issued and sold										3,200,000
Sale of stock price per share							$ 25.09	$ 25.09		$ 25.09
Gross proceeds from issuance of stock										$ 80,500
Proceeds from issuance of offering										$ 79,100