13. Employee Benefits (Details - Fair Value of Plan Assets) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Fair value of plan assets	$ 19,848	$ 21,664	$ 16,612
Company Common Stock [Member]
Fair value of plan assets	6,542	8,319
Large Cap Value [Member]
Fair value of plan assets	2,378
Mid Cap Index [Member]
Fair value of plan assets	682
Small Cap Growth [Member]
Fair value of plan assets	691
Small Cap Value [Member]
Fair value of plan assets	673
Focus Value [Member]
Fair value of plan assets	700	692
Growth [Member]
Fair value of plan assets	2,383	3,237
International Growth [Member]
Fair value of plan assets	2,649	2,855
Core Bond [Member]
Fair value of plan assets	1,969	1,870
High Yield [Member]
Fair value of plan assets	382	387
Inflation Protected Bond [Member]
Fair value of plan assets	518	487
Money Market [Member]
Fair value of plan assets	281	31
Fundamental Value [Member]
Fair value of plan assets		2,384
Mid Cap Growth [Member]
Fair value of plan assets		709
Small Co. Value [Member]
Fair value of plan assets		693
Level 1 [Member]
Fair value of plan assets	6,542	8,319
Level 1 [Member] | Company Common Stock [Member]
Fair value of plan assets	6,542	8,319
Level 1 [Member] | Large Cap Value [Member]
Fair value of plan assets	0
Level 1 [Member] | Mid Cap Index [Member]
Fair value of plan assets	0
Level 1 [Member] | Small Cap Growth [Member]
Fair value of plan assets	0
Level 1 [Member] | Small Cap Value [Member]
Fair value of plan assets	0
Level 1 [Member] | Focus Value [Member]
Fair value of plan assets	0	0
Level 1 [Member] | Growth [Member]
Fair value of plan assets	0	0
Level 1 [Member] | International Growth [Member]
Fair value of plan assets	0	0
Level 1 [Member] | Core Bond [Member]
Fair value of plan assets	0	0
Level 1 [Member] | High Yield [Member]
Fair value of plan assets	0	0
Level 1 [Member] | Inflation Protected Bond [Member]
Fair value of plan assets	0	0
Level 1 [Member] | Money Market [Member]
Fair value of plan assets	0	0
Level 1 [Member] | Fundamental Value [Member]
Fair value of plan assets		0
Level 1 [Member] | Mid Cap Growth [Member]
Fair value of plan assets		0
Level 1 [Member] | Small Co. Value [Member]
Fair value of plan assets		0
Level 2 [Member]
Fair value of plan assets	13,306	13,345
Level 2 [Member] | Company Common Stock [Member]
Fair value of plan assets	0	0
Level 2 [Member] | Large Cap Value [Member]
Fair value of plan assets	2,378
Level 2 [Member] | Mid Cap Index [Member]
Fair value of plan assets	682
Level 2 [Member] | Small Cap Growth [Member]
Fair value of plan assets	691
Level 2 [Member] | Small Cap Value [Member]
Fair value of plan assets	673
Level 2 [Member] | Focus Value [Member]
Fair value of plan assets	700	692
Level 2 [Member] | Growth [Member]
Fair value of plan assets	2,383	3,237
Level 2 [Member] | International Growth [Member]
Fair value of plan assets	2,649	2,855
Level 2 [Member] | Core Bond [Member]
Fair value of plan assets	1,969	1,870
Level 2 [Member] | High Yield [Member]
Fair value of plan assets	382	387
Level 2 [Member] | Inflation Protected Bond [Member]
Fair value of plan assets	518	487
Level 2 [Member] | Money Market [Member]
Fair value of plan assets	281	31
Level 2 [Member] | Fundamental Value [Member]
Fair value of plan assets		2,384
Level 2 [Member] | Mid Cap Growth [Member]
Fair value of plan assets		709
Level 2 [Member] | Small Co. Value [Member]
Fair value of plan assets		693
Level 3 [Member]
Fair value of plan assets	0	0
Level 3 [Member] | Company Common Stock [Member]
Fair value of plan assets	0	0
Level 3 [Member] | Large Cap Value [Member]
Fair value of plan assets	0
Level 3 [Member] | Mid Cap Index [Member]
Fair value of plan assets	0
Level 3 [Member] | Small Cap Growth [Member]
Fair value of plan assets	0
Level 3 [Member] | Small Cap Value [Member]
Fair value of plan assets	0
Level 3 [Member] | Focus Value [Member]
Fair value of plan assets	0	0
Level 3 [Member] | Growth [Member]
Fair value of plan assets	0	0
Level 3 [Member] | International Growth [Member]
Fair value of plan assets	0	0
Level 3 [Member] | Core Bond [Member]
Fair value of plan assets	0	0
Level 3 [Member] | High Yield [Member]
Fair value of plan assets	0	0
Level 3 [Member] | Inflation Protected Bond [Member]
Fair value of plan assets	0	0
Level 3 [Member] | Money Market [Member]
Fair value of plan assets	0	0
Level 3 [Member] | Fundamental Value [Member]
Fair value of plan assets		0
Level 3 [Member] | Mid Cap Growth [Member]
Fair value of plan assets		0
Level 3 [Member] | Small Co. Value [Member]
Fair value of plan assets		$ 0