Note 1. Principal Accounting Policies Earnings per share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Earnings Per Share [Abstract]
Net income	$ 12,893	$ 14,005
Weighted average common shares outstanding	56,957,433	56,096,637
Stock options and nonvested stock	582,635	635,335
Weighted average common shares outstanding, diluted	57,540,068	56,731,972
Diluted earnings per share	$ 0.22	$ 0.25
Anti-dilutive securities excluded from computation of diluted EPS	899,241	1,141,137