Consolidated Statement of Changes in Shareholders' Equity (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Issuance of 1,437 shares for exercise of options, including tax effect	2,079	1,458	1,404
Purchase of 4,543 common shares	5,567	12,645	1,301
Cash dividends declared $0.475 per share	$ 0.64	$ 0.60	$ 0.56