Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Net income	$ 21,049	$ 17,452	$ 42,059	$ 35,337
Change in net unrealized (loss) gain on available-for-sale (AFS) securities, net of tax	(1,709)	(250)	(865)	634
Accretion of the net unrealized loss on the transfer of AFS securities to held-to-maturity (HTM) securities, net of tax	1	1	2	2
Change in pension plan assets, net of tax	620	342	1,238	685
Comprehensive income, net of tax	$ 19,961	$ 17,545	$ 42,434	$ 36,658