CONDENSED STATEMENTS OF CONSOLIDATED COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Net income	$ 26,125	$ 26,015	$ 101,657	$ 83,206
Unrealized gains on securities:
Change in unrealized holding gains, net	32,256	37,526	52,410	98,039
Less: Reclassifications adjustment for gains included in net income	(259)	(2,411)	(20,022)	(15,891)
Change in unrealized gains on securities during the period	31,997	35,115	32,388	82,148
Income tax expense	(11,827)	(12,940)	(12,074)	(30,327)
Other comprehensive income	20,170	22,175	20,314	51,821
Comprehensive income	$ 46,295	$ 48,190	$ 121,971	$ 135,027