Shareholders' Equity (Statement of Equity) (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	$ 192,424,000
Net income	4,198,000	3,857,000
Other comprehensive income (loss), net of tax	(232,000)
Exercise of stock options (in shares)	59,204
Exercise of stock options	1,080,000
Issuance of restricted common stock for services (in shares)	4,020	4,685
Issuance of restricted common stock for services	94,000	86,000
Issuance of common stock under Employee Stock Purchase Plan (in shares)	8,802	11,364
Issuance of common stock under Employee Stock Purchase Plan	169,000
Compensation cost of stock options	461,000
Balance	198,194,000
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance (in shares)	13,577,000
Balance	136,000
Exercise of stock options (in shares)	59,000
Exercise of stock options	0
Issuance of restricted common stock for services (in shares)	4,000
Issuance of restricted common stock for services	0
Issuance of common stock under Employee Stock Purchase Plan (in shares)	9,000
Issuance of common stock under Employee Stock Purchase Plan	0
Balance (in shares)	13,649,000
Balance	136,000
Additional Paid-In Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	69,175,000
Exercise of stock options	1,080,000
Issuance of restricted common stock for services	94,000
Issuance of common stock under Employee Stock Purchase Plan	169,000
Compensation cost of stock options	461,000
Balance	70,979,000
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	127,015,000
Net income	4,198,000
Balance	131,213,000
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	(3,902,000)
Other comprehensive income (loss), net of tax	(232,000)
Balance	$ (4,134,000)