Consolidated Statement Of Changes In Equity (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Statement of Stockholders' Equity [Abstract]
Cancellation of employee nonvested shares	0	355	5,411
Non-cash payment received on shareholder loans, common shares	0	86,056
Purchase of common shares for treasury	66,368	61,869	40,565
Issuances of common shares, costs	$ 0	$ 6,623	$ 727