Consolidated Statements of Comprehensive Income - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Net income	$ 72,433,000	$ 69,053,000	$ 142,357,000	$ 137,011,000
Other comprehensive income (loss), net of tax:
Net change in pensions and other benefits	(594,000)		(594,000)
Net change in investment securities	47,364,000	(18,039,000)	100,805,000	(66,816,000)
Net change in cash flow derivative hedges		313,000		857,000
Other comprehensive income (loss)	46,770,000	(17,726,000)	100,211,000	(65,959,000)
Total comprehensive income	$ 119,203,000	$ 51,327,000	$ 242,568,000	$ 71,052,000