Earnings per Share (Details 1) - shares	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Schedule Of Common Stock Outstanding [Roll Forward]
Outstanding, beginning of year	5,616,607	5,441,190	5,441,190
Issuance of stock: 4% stock dividend	0	0	217,155
Purchase of treasury stock	(1,400)	(8,635)	(41,738)
Outstanding, end of year	5,615,207	5,432,555	5,616,607