7. Income Per Share (Details - Basic and diluted) - 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
Earnings Per Share [Abstract]
Net Income	$ 5,571	$ 7,614	$ 7,450	$ 6,945	$ 6,050	$ 7,799	$ 7,474	$ 7,602	$ 27,581	$ 28,925	$ 27,808
Weighted Average Basic Shares Outstanding									1,824	1,846	1,958
Add: Effect of dilutive securities									33	24	17
Weighted average diluted shares outstanding									1,857	1,870	1,975
Net Income per share
Basic	$ 3.05	$ 4.17	$ 4.09	$ 3.81	$ 3.32	$ 4.25	$ 4.04	$ 4.05	$ 15.12	$ 15.67	$ 14.20
Diluted	$ 3.00	$ 4.10	$ 4.02	$ 3.76	$ 3.27	$ 4.19	$ 3.99	$ 4.01	$ 14.85	$ 15.47	$ 14.08