Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Net income	$ 117,844	$ 93,131	$ 335,665	$ 263,625
Other comprehensive income (loss), before tax:
Change in net unrealized gain/loss on securities available for sale during the period	(96,147)	7,082	(286,935)	131,283
Change in net unrealized gain on securities transferred to held to maturity	(3,764)	(3,514)	(8,424)	(13,660)
Reclassification adjustment for net (gains) losses included in net income	34	4,867	113	4,917
Total securities available for sale and transferred securities, before tax amount	(99,877)	8,435	(295,246)	122,540
Defined-benefit post-retirement benefit plans:
Change in the net actuarial gain/loss	0	0	0	0
Reclassification adjustment for net amortization of actuarial gain/loss included in net income as a component of net periodic cost (benefit)	1,250	1,357	3,751	4,072
Total defined-benefit post-retirement benefit plans	1,250	1,357	3,751	4,072
Other comprehensive income (loss), before tax	(98,627)	9,792	(291,495)	126,612
Deferred tax expense (benefit) related to other comprehensive income	(20,711)	3,427	(61,213)	44,314
Other comprehensive income (loss), net of tax	(77,916)	6,365	(230,282)	82,298
Comprehensive income (loss)	$ 39,928	$ 99,496	$ 105,383	$ 345,923