Selected Quarterly Information (Unaudited) (Notes)

12 Months Ended

Dec. 31, 2017

Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Information [Text Block]

SELECTED QUARTERLY INFORMATION (UNAUDITED)

	Year Ended December 31, 2017
	First Quarter			Second Quarter			Third Quarter			Fourth Quarter
Operating results:
Interest income	$	22,419		$	24,856		$	23,103		$	24,124
Interest expense	7,519			8,714			9,889			10,056
Net interest income	14,900			16,142			13,214			14,068
Gain (loss) on derivatives instruments, net	175			(15,802		)	5,993			12,678
Loss on sale of investments, net	(1,708		)	(3,709		)	(5,211		)	(902		)
Fair value adjustments and other income (expense) amounts, net	(36		)	34			(86		)	(38		)
General and administrative expenses	(4,280		)	(4,097		)	(3,599		)	(3,843		)
Preferred stock dividends	(2,435		)	(2,641		)	(2,808		)	(2,910		)
Net income (loss) to common shareholders	6,616			(10,073		)	7,503			19,053
Other comprehensive income (loss)	19,977			12,375			6,144			(14,584		)
Comprehensive income (loss) to common shareholders	$	26,593		$	2,302		$	13,647		$	4,469
Net income (loss) per common share	$	0.13		$	(0.20	)	$	0.15		$	0.36
Dividends declared per common share	$	0.18		$	0.18		$	0.18		$	0.18
	Year Ended December 31, 2016
	First Quarter			Second Quarter			Third Quarter			Fourth Quarter
Operating results:
Interest income	$	25,089		$	22,816		$	21,135		$	22,858
Interest expense	6,310			6,100			6,068			6,753
Net interest income	18,779			16,716			15,067			16,105
(Loss) gain on derivatives instruments, net	(48,264		)	(16,297		)	2,409			56,546
Loss on sale of investments, net	(3,941		)	(297		)	—			—
Fair value adjustments and other income (expense) amounts, net	87			318			579			(1		)
General and administrative expenses	(4,092		)	(3,671		)	(3,355		)	(3,589		)
Preferred stock dividends	(2,294		)	(2,294		)	(2,294		)	(2,303		)
Net (loss) income to common shareholders	(39,725		)	(5,525		)	12,406			66,758
Other comprehensive income (loss)	41,728			22,947			670			(85,186		)
Comprehensive income (loss) to common shareholders	$	2,003		$	17,422		$	13,076		$	(18,428	)
Net (loss) income per common share	$	(0.81	)	$	(0.11	)	$	0.25		$	1.36
Dividends declared per common share	$	0.21		$	0.21		$	0.21		$	0.21