14. Employee Benefits - Fair Value of Plan Assets (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Fair value of plan assets	$ 21,664	$ 16,612	$ 10,613
Company Common Stock [Member]
Fair value of plan assets	8,319	4,791
Fundamental Value [Member]
Fair value of plan assets	2,384	2,049
Mid Cap Growth [Member]
Fair value of plan assets	709	596
Focus Value [Member]
Fair value of plan assets	692	607
Small Co. Value [Member]
Fair value of plan assets	693	604
Growth [Member]
Fair value of plan assets	3,237	2,681
International Growth [Member]
Fair value of plan assets	2,855	2,431
Core Bond [Member]
Fair value of plan assets	1,870	1,780
High Yield [Member]
Fair value of plan assets	387
Income [Member]
Fair value of plan assets		363
Inflation Protected Bond [Member]
Fair value of plan assets	487	472
Money Market [Member]
Fair value of plan assets	31	238
Level 1 [Member]
Fair value of plan assets	8,319	0
Level 1 [Member] \| Company Common Stock [Member]
Fair value of plan assets	8,319	4,791
Level 1 [Member] \| Fundamental Value [Member]
Fair value of plan assets	0	0
Level 1 [Member] \| Mid Cap Growth [Member]
Fair value of plan assets	0	0
Level 1 [Member] \| Focus Value [Member]
Fair value of plan assets	0	0
Level 1 [Member] \| Small Co. 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
Level 1 [Member] \| Income [Member]
Fair value of plan assets		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 2 [Member]
Fair value of plan assets	13,345	11,821
Level 2 [Member] \| Company Common Stock [Member]
Fair value of plan assets	0	0
Level 2 [Member] \| Fundamental Value [Member]
Fair value of plan assets	2,384	2,049
Level 2 [Member] \| Mid Cap Growth [Member]
Fair value of plan assets	709	596
Level 2 [Member] \| Focus Value [Member]
Fair value of plan assets	692	607
Level 2 [Member] \| Small Co. Value [Member]
Fair value of plan assets	693	604
Level 2 [Member] \| Growth [Member]
Fair value of plan assets	3,237	2,681
Level 2 [Member] \| International Growth [Member]
Fair value of plan assets	2,855	2,431
Level 2 [Member] \| Core Bond [Member]
Fair value of plan assets	1,870	1,780
Level 2 [Member] \| High Yield [Member]
Fair value of plan assets	387
Level 2 [Member] \| Income [Member]
Fair value of plan assets		363
Level 2 [Member] \| Inflation Protected Bond [Member]
Fair value of plan assets	487	472
Level 2 [Member] \| Money Market [Member]
Fair value of plan assets	31	238
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] \| Fundamental Value [Member]
Fair value of plan assets	0	0
Level 3 [Member] \| Mid Cap Growth [Member]
Fair value of plan assets	0	0
Level 3 [Member] \| Focus Value [Member]
Fair value of plan assets	0	0
Level 3 [Member] \| Small Co. 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
Level 3 [Member] \| Income [Member]
Fair value of plan assets		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