Note 6 - Earnings Per Common Share (Details) - Basic and Diluted Earnings Per Common Share (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Numerator:
Net income (in Dollars)	$ 7,301	$ 7,977	$ 7,667	$ 7,202	$ 7,719	$ 6,518	$ 7,584	$ 5,446	$ 30,147	$ 27,267	$ 24,285
Denominator:
Basic earnings per common share - weighted-average shares									33,221	33,095	32,969
Effect of dilutive stock options									208	130	144
Diluted earnings per common share - weighted-average shares and assumed conversions									33,429	33,225	33,113
Basic earnings per common share (in Dollars per share)	$ 0.22	$ 0.24	$ 0.23	$ 0.22	$ 0.23	$ 0.20	$ 0.23	$ 0.16	$ 0.91	$ 0.82	$ 0.74
Diluted earnings per common share (in Dollars per share)	$ 0.22	$ 0.24	$ 0.23	$ 0.22	$ 0.23	$ 0.20	$ 0.23	$ 0.16	$ 0.90	$ 0.82	$ 0.73