Quarterly Results (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Interest income	$ 25,068,000	$ 22,358,000	$ 19,235,000	$ 20,466,000	$ 19,092,000	$ 18,352,000	$ 16,753,000	$ 14,614,000
Interest Expense	4,976,000	3,979,000	3,330,000	3,319,000	2,371,000	2,037,000	1,567,000	1,296,000
Net interest income	20,092,000	18,379,000	15,905,000	17,147,000	16,721,000	16,315,000	15,186,000	13,318,000
Realized And Unrealized Gains	(38,003,000)	4,418,000	(7,308,000)	(19,558,000)	(6,813,000)	(23,682,000)	(16,017,000)	(6,063,000)
Net portfolio income	(17,911,000)	22,797,000	8,597,000	(2,411,000)	9,908,000	(7,367,000)	(831,000)	7,255,000
Management Fee Expense	1,557,000	1,388,000	1,274,000	1,269,000	1,338,000	1,321,000	1,288,000	1,095,000
Other Expenses	951,000	883,000	860,000	911,000	759,000	729,000	713,000	651,000
Total expenses	2,508,000	2,271,000	2,134,000	2,180,000	2,097,000	2,050,000	2,001,000	1,746,000
Net income (loss)	$ (20,419,000)	$ 20,526,000	$ 6,463,000	$ (4,591,000)	$ 7,811,000	$ (9,417,000)	$ (2,832,000)	$ 5,509,000
Earnings Per Share, Basic	$ (0.72)	$ 0.85	$ 0.29	$ (0.21)	$ 0.36	$ (0.42)	$ (0.14)	$ 0.54	$ 0.08	$ 0.05	$ 2.48
Earnings Per Share Diluted	$ (0.72)	$ 0.85	$ 0.29	$ (0.21)	$ 0.36	$ (0.42)	$ (0.14)	$ 0.54	$ 0.08	$ 0.05	$ 2.48
Weighted Average Number Of Basic Shares Outstanding	28,494,000	24,133,000	21,921,000	21,756,000	21,771,000	22,545,000	19,752,000	16,847,000	24,099,714	20,266,706	9,890,058
Weighted Average Number Of Diluted Shares Outstanding	28,494,000	24,133,000	21,921,000	21,756,000	21,771,000	22,545,000	19,752,000	16,847,000	24,099,714	20,266,706	9,890,058
Dividends Declared Per Common Share	$ 0.42	$ 0.42	$ 0.42	$ 0.42	$ 0.42	$ 0.42	$ 0.54	$ 0.54	$ 1.68	$ 1.92	$ 2.16