Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Net income	$ 71,479	$ 73,077	$ 140,258	$ 145,240
Other comprehensive income (loss), before tax:
Change in net unrealized gain/loss on securities available for sale during the period	165,288	(113,268)	287,506	(78,741)
Change in net unrealized gain on securities transferred to held to maturity	(9,185)	(8,207)	(17,351)	(16,094)
Reclassification adjustment for net (gains) losses included in net income	0	0	(14,903)	(228)
Total securities available for sale and transferred securities, before tax amount	156,103	(121,475)	255,252	(95,063)
Defined-benefit post-retirement benefit plans:
Change in the net actuarial gain/loss	1,553	1,749	3,106	3,498
Remeasurement of projected benefit obligation related to SERP	(862)	0	(862)	0
Reclassification adjustment for SERP settlement costs included in net income	187	0	187	0
Total defined-benefit post-retirement benefit plans	878	1,749	2,431	3,498
Other comprehensive income (loss), before tax	156,981	(119,726)	257,683	(91,565)
Deferred tax expense (benefit) related to other comprehensive income	54,943	(41,904)	90,189	(32,048)
Other comprehensive income (loss), net of tax	102,038	(77,822)	167,494	(59,517)
Comprehensive income (loss)	$ 173,517	$ (4,745)	$ 307,752	$ 85,723