Capitalization (Schedule of Earnings Per Share) (Details) - USD ($) $ / shares in Units, $ in Thousands	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
Basic:
Net Income	$ 3,220	$ 8,813	$ 5,919	$ 4,790	$ 4,560	$ 6,743	$ 5,089	$ 3,636	$ 22,742	$ 20,028	$ 18,445
Preferred Dividend									(144)	(144)	(151)
Earnings Applicable to Common Stock									$ 22,598	$ 19,884	$ 18,294
Weighted-average number of basic shares outstanding, shares									16,270,000	16,175,000	16,052,000
Basic EPS	$ 0.20	$ 0.54	$ 0.36	$ 0.29	$ 0.29	$ 0.41	$ 0.31	$ 0.22	$ 1.39	$ 1.23	$ 1.14
Diluted:
$7.00 Series Preferred Dividend									$ 67	$ 67	$ 74
$8.00 Series Preferred Dividend									24	24	24
Adjusted Earnings Applicable to Common Stock									$ 22,689	$ 19,975	$ 18,392
Incremental common shares attributable to $7.00 series preferred shares, shares									115,000	115,000	133,000
Incremental common shares attributable to $8.00 series preferred shares, shares									41,000	41,000	41,000
Weighted-average diluted shares outstanding, shares									16,426,000	16,331,000	16,226,000
Diluted EPS	$ 0.19	$ 0.54	$ 0.36	$ 0.29	$ 0.28	$ 0.41	$ 0.31	$ 0.22	$ 1.38	$ 1.22	$ 1.13