Consolidated Statements of Comprehensive Earnings (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Amounts Reclassified Out Of Accumulated Other Comprehensive Income Loss [Abstract]
NET EARNINGS	$ 25,886	$ 23,431	$ 75,189	$ 66,972
OTHER ITEMS OF COMPREHENSIVE EARNINGS (LOSS):
Change in unrealized gain on investment securities available-for-sale, before income taxes	23,025	5,707	5,318	43,889
Reclassification adjustment for realized losses (gains) on investment securities included in net earnings, before income tax	(136)	(1)	(380)	4
Minimum liability pension adjustment, before income taxes	(108)		(216)
Total other items of comprehensive earnings (losses)	22,781	5,706	4,722	43,893
Income tax benefit (expense) related to:
Investment securities	(8,011)	(1,997)	(1,728)	(15,362)
Minimum liability pension adjustment	38		76
Total income tax benefit (expense)	(7,973)	(1,997)	(1,652)	(15,362)
COMPREHENSIVE EARNINGS	$ 40,694	$ 27,140	$ 78,259	$ 95,503