Restatement (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Other income and expense:
Operating Income (Loss)	$ 4,487	$ 5,002	$ 9,739	$ 9,668
Interest and other income	14	14	34	24
Interest expense	1,599	1,590	3,010	2,319
Total other expense	(1,585)	(1,576)	(2,976)	(2,295)
Income before income taxes	2,902	3,426	6,763	7,373
Net income	1,738	2,348	4,032	4,694
Other comprehensive income, net of taxes	(543)	66	(464)	131
Total comprehensive income	1,195	2,414	3,568	4,825
Basic earnings per share	$ 0.13	$ 0.18	$ 0.30	$ 0.35
Diluted earnings per share	$ 0.13	$ 0.18	$ 0.30	$ 0.35
Shareholders' equity:
Common stock	1,349		1,349		1,340
Additional paid-in capital	16,211		16,211		15,683
Retained earnings	30,573		30,573		30,309
Accumulated other comprehensive (loss)	(4,599)		(4,599)		(4,135)
Total shareholders' equity	43,534		43,534		43,197
Scenario Previously Reported [Member]
Other income and expense:
Operating Income (Loss)	4,487	5,002	9,739	9,668
Interest and other income	14	14	34	24
Interest expense	(1,482)	(1,015)	(2,846)	(2,083)
Total other expense	(1,468)	(1,001)	(2,812)	(2,059)
Income before income taxes	3,019	4,001	6,927	7,609
Income tax provision	1,210	1,307	2,796	2,773
Net income	1,809	2,694	4,131	4,836
Other comprehensive income, net of taxes	(614)	(280)	(563)	(11)
Total comprehensive income	1,195	2,414	3,568	4,825
Basic earnings per share	$ 0.13	$ 0.20	$ 0.31	$ 0.36
Diluted earnings per share	$ 0.13	$ 0.20	$ 0.31	$ 0.36
Shareholders' equity:
Common stock	1,349		1,349		1,340
Additional paid-in capital	16,211		16,211		15,683
Retained earnings	32,160		32,160		31,797
Accumulated other comprehensive (loss)	(6,186)		(6,186)		(5,623)
Total shareholders' equity	43,534		43,534		43,197
Restatement Adjustment [Member]
Other income and expense:
Operating Income (Loss)	0	0	0	0
Interest and other income	0	0	0	0
Interest expense	(117)	(575)	(164)	(236)
Total other expense	(117)	(575)	(164)	(236)
Income before income taxes	(117)	(575)	(164)	(236)
Income tax provision	(46)	(229)	(65)	(94)
Net income	(71)	(346)	(99)	(142)
Other comprehensive income, net of taxes	71	346	99	142
Total comprehensive income	0	0	0	0
Basic earnings per share	$ 0	$ (0.02)	$ (0.01)	$ (0.01)
Diluted earnings per share	$ 0	$ (0.02)	$ (0.01)	$ (0.01)
Shareholders' equity:
Common stock	0		0		0
Additional paid-in capital	0		0		0
Retained earnings	(1,587)		(1,587)		(1,488)
Accumulated other comprehensive (loss)	1,587		1,587		1,488
Total shareholders' equity	$ 0		$ 0		$ 0