Note 19 - Earnings Per Share - Computation of Earnings Per Share (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
Net income attributable to common shares	$ 8,085,000,000	$ 7,845,000,000	$ 7,434,000,000	$ 8,549,000,000	$ 6,480,000,000	$ 7,336,000,000	$ 6,558,000,000	$ 6,646,000,000	$ 31,913,000	$ 27,020,000	$ 17,331,000
Weighted average common shares outstanding (in shares)									16,292,086	16,609,263	13,510,991
Basic earnings per common share (in dollars per share)	$ 0.49	$ 0.48	$ 0.46	$ 0.52	$ 0.40	$ 0.45	$ 0.39	$ 0.39	$ 1.96	$ 1.63	$ 1.28
Net income attributable to common shares	$ 8,085,000,000	$ 7,845,000,000	$ 7,434,000,000	$ 8,549,000,000	$ 6,480,000,000	$ 7,336,000,000	$ 6,558,000,000	$ 6,646,000,000	$ 31,913,000	$ 27,020,000	$ 17,331,000
Weighted average common shares outstanding for basic earnings per common share (in shares)									16,292,086	16,609,263	13,510,991
Add: Dilutive effects of share-based awards (in shares)									18,644	32,877	30,913
Average shares and dilutive potential common shares (in shares)									16,310,730	16,642,140	13,541,904
Diluted earnings per common share (in dollars per share)	$ 0.49	$ 0.48	$ 0.46	$ 0.52	$ 0.40	$ 0.45	$ 0.39	$ 0.39	$ 1.96	$ 1.62	$ 1.28