Consolidated Statements of Changes in Stockholders Equity (Unaudited) (USD $) In Thousands, unless otherwise specified	Total	Common stock	Retained earnings	Accumulated other comprehensive income
Beginning Balance at Dec. 31, 2012	$ 751,186	$ 271,335	$ 463,860	$ 15,991
Comprehensive income:
Net income	20,044	0	20,044	0
Other comprehensive income, net of tax	(3,451)	0	0	(3,451)
Common stock transactions:
Common shares purchased and retired 124,867 and 25,677 in 2014 and 2013 respectively	(448)	(448)	0	0
Non-vested common shares issued 147,876 and 108,873 in 2014 and 2013 respectively	0	0	0	0
3,782 and 1,815 non-vested common shares forfeited in 2014 and 2013 respectively	0	0	0	0
215,805 and 243,238 stock options exercised, net of 152,131 and 87,933 shares tendered in payment of option price and income tax withholding amounts in 2014 and 2013 respectively	3,145	3,145	0	0
Tax benefit of stock-based compensation	202	202	0	0
Stock-based compensation expense	695	695	0	0
Ending Balance at Mar. 31, 2013	771,373	274,929	483,904	12,540
Beginning Balance at Dec. 31, 2013	801,581	285,535	532,087	(16,041)
Comprehensive income:
Net income	21,393	0	21,393	0
Other comprehensive income, net of tax	8,682	0	0	8,682
Common stock transactions:
Common shares purchased and retired 124,867 and 25,677 in 2014 and 2013 respectively	(3,159)	(3,159)	0	0
Non-vested common shares issued 147,876 and 108,873 in 2014 and 2013 respectively	0	0	0	0
3,782 and 1,815 non-vested common shares forfeited in 2014 and 2013 respectively	0	0	0	0
215,805 and 243,238 stock options exercised, net of 152,131 and 87,933 shares tendered in payment of option price and income tax withholding amounts in 2014 and 2013 respectively	2,476	2,476	0	0
Tax benefit of stock-based compensation	989	989	0	0
Stock-based compensation expense	712	712	0	0
Cash dividends declared:
Common ($0.16) per share in 2014	(7,036)	0	(7,036)	0
Ending Balance at Mar. 31, 2014	$ 825,638	$ 286,553	$ 546,444	$ (7,359)