Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Net income	$ 84,941	$ 68,816
Other comprehensive income (loss), before tax:
Change in net unrealized gain/loss on securities available for sale during the period	33,811	122,218
Change in net unrealized gain on securities transferred to held to maturity	(6,286)	(8,166)
Reclassification adjustment for net (gains) losses included in net income	0	(14,903)
Total securities available for sale and transferred securities, before tax amount	27,525	99,149
Defined-benefit post-retirement benefit plans:
Reclassification adjustment for net amortization of actuarial gain/loss included in net income as a component of net periodic cost (benefit)	1,357	1,553
Total defined-benefit post-retirement benefit plans	1,357	1,553
Other comprehensive income (loss), before tax	28,882	100,702
Deferred tax expense (benefit) related to other comprehensive income	10,109	35,246
Other comprehensive income (loss), net of tax	18,773	65,456
Comprehensive income (loss)	$ 103,714	$ 134,272