Interim Condensed Consolidated Statements of Comprehensive Income (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Net Income	$ 12,676	$ 18,724
Other comprehensive income:
Unrealized gains on investments in marketable securities	7,969	5,644
Income tax expense related to items of other comprehensive income	(3,110)	(2,205)
Other comprehensive income, net of tax	4,859	3,439
Comprehensive Income	$ 17,535	$ 22,163