CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock	Accumulated Other Comprehensive Income (Loss)	Retained Earnings
BALANCE at Dec. 31, 2012	$ 342,417	$ 164,790	$ 6,811	$ 170,816
BALANCE (in shares) at Dec. 31, 2012		71,295,144
Increase (Decrease) in Shareholders' Equity
Stock options exercised	10	10
Stock options exercised (in shares)		1,812
Cash dividend declared or accrued:
Share-based compensation expense	115	115
Net income	11,589			11,589
Other comprehensive income (loss)	(418)		(418)
BALANCE at Mar. 31, 2013	353,713	164,915	6,393	182,405
BALANCE (in shares) at Mar. 31, 2013		71,296,956
BALANCE at Dec. 31, 2013	439,418	229,836	(23)	209,605
BALANCE (in shares) at Dec. 31, 2013		78,061,307
Increase (Decrease) in Shareholders' Equity
Stock options exercised	461	461
Stock options exercised (in shares)		113,769
Restricted stock granted (in shares)		71,950
Cash dividend declared or accrued:
Common stock ($0.05 per share)	(3,912)			(3,912)
Share-based compensation expense	433	433
Tax benefit from stock options exercised	249	249
Net income	13,113			13,113
Other comprehensive income (loss)	1,813		1,813
BALANCE at Mar. 31, 2014	$ 451,575	$ 230,979	$ 1,790	$ 218,806
BALANCE (in shares) at Mar. 31, 2014		78,247,026