Capitalization (Schedule of Earnings Per Share) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Basic:
Net Income	$ 8,307	$ 12,737	$ 9,713	$ 7,668	$ 8,071	$ 11,119	$ 8,146	$ 6,552	$ 38,425	$ 33,888	$ 32,452
Preferred Dividend									(120)	(132)	(144)
Earnings Applicable to Common Stock									$ 38,305	$ 33,756	$ 32,308
Weighted-average number of basic shares outstanding, shares									17,459	16,685	16,384
Basic EPS	$ 0.47	$ 0.73	$ 0.55	$ 0.44	$ 0.46	$ 0.67	$ 0.49	$ 0.40	$ 2.19	$ 2.02	$ 1.97
Diluted:
$7.00 Series Preferred Dividend									$ 67	$ 67	$ 67
$8.00 Series Preferred Dividend										12	24
Adjusted Earnings Applicable to Common Stock									$ 38,372	$ 33,835	$ 32,399
Incremental common shares attributable to $7.00 series preferred shares, shares									115	115	115
Incremental common shares attributable to $8.00 series preferred shares, shares										29	41
Weighted-average diluted shares outstanding, shares									17,574	16,829	16,540
Diluted EPS	$ 0.47	$ 0.72	$ 0.55	$ 0.44	$ 0.46	$ 0.67	$ 0.49	$ 0.39	$ 2.18	$ 2.01	$ 1.96