CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Net earnings	$ 24,163	$ 4,349	$ 16,088	$ 42,006	$ 36,909
Other comprehensive income (loss) related to unrealized gains (losses) on securities available-for-sale:
Unrealized holding gains (losses) arising during the period	4,070	(48,189)	12,966	(50,529)	28,560
Income tax benefit (expense) related to unrealized holding (losses) gains arising during the period	483	20,240	(5,445)	23,415	(11,995)
Reclassification adjustment for (gain) loss included in net earnings	(5,222)			(5,631)	1,115
Income tax (benefit) expense related to reclassification adjustment				172	(468)
Other comprehensive income (loss)	(669)	(27,949)	7,521	(32,573)	17,212
Comprehensive income (loss)	$ 23,494	$ (23,600)	$ 23,609	$ 9,433	$ 54,121