Note 1. Principal Accounting Policies Earnings per share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Earnings Per Share [Abstract]
Net income	$ 45,583	$ 30,557	$ 112,143	$ 87,459
Weighted-average common shares outstanding	57,692,508	56,714,423	57,262,132	56,390,621
Stock options and nonvested stock	561,055	648,411	570,001	674,525
Weighted-average common shares outstanding, diluted	58,253,563	57,362,834	57,832,133	57,065,146
Diluted EPS	$ 0.78	$ 0.53	$ 1.94	$ 1.53
Anti-dilutive securities excluded from calculation of diluted EPS	157,000	930,616	518,570	954,749