Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2020	Dec. 31, 2019
Common stock, par value	$ 0.10	$ 0.10
Common stock, shares authorized	143,664,000	123,664,000
Common stock, shares issued	41,301,000	41,130,000
Common stock, shares outstanding	41,301,000	41,130,000
Excess stock, par value	$ 0.10	$ 0.10
Excess stock, shares authorized	3,000,000	3,000,000
Excess stock, shares issued	0	0
Excess stock, shares outstanding	0	0
Series B Preferred Stock [Member]
Percentage rate on cumulative redeemable preferred stock	8.00%	8.00%
Cumulative redeemable preferred stock, par value	$ 0.10	$ 0.10
Cumulative redeemable preferred stock, shares authorized	4,000,000	4,000,000
Cumulative redeemable preferred stock, shares issued	3,801,000	3,801,000
Cumulative redeemable preferred stock, shares outstanding	3,801,000	3,801,000
Series C Preferred Stock [Member]
Percentage rate on cumulative redeemable preferred stock	6.75%	6.75%
Cumulative redeemable preferred stock, par value	$ 0.10	$ 0.10
Cumulative redeemable preferred stock, shares authorized	13,750,000	13,750,000
Cumulative redeemable preferred stock, shares issued	9,750,000	9,750,000
Cumulative redeemable preferred stock, shares outstanding	9,750,000	9,750,000
Series D Preferred Stock [Member]
Percentage rate on cumulative redeemable preferred stock	6.375%	6.375%
Cumulative redeemable preferred stock, par value	$ 0.10	$ 0.10
Cumulative redeemable preferred stock, shares authorized	6,000,000	6,000,000
Cumulative redeemable preferred stock, shares issued	5,211,000	2,651,000
Cumulative redeemable preferred stock, shares outstanding	5,211,000	2,651,000