Accumulated Other Comrehensive Loss (Components of AOCI) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amounts reclassified from accumulated other comprehensive income	$ (5,776)	$ (27,276)
Net current period other comprehensive (loss) income	(2,487)	138,986	$ 108,464
Unrealized (losses) gains on securities available for sale
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Stockholders' equity	78,754	5,792
Net unrealized gains arising during period	(62,332)	119,357
Amounts reclassified from accumulated other comprehensive income	(25,502)	(46,395)
Net current period other comprehensive (loss) income	(87,834)	72,962
Stockholders' equity	(9,080)	78,754	5,792
Unrealized (losses) gains on securities available for sale transferred to held to maturity
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Stockholders' equity	4,157	0
Net unrealized gains arising during period	(9,747)	4,538
Amounts reclassified from accumulated other comprehensive income	(1,136)	(381)
Net current period other comprehensive (loss) income	(10,883)	4,157
Stockholders' equity	(6,726)	4,157	0
Defined Benefit Pension Items
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Stockholders' equity	(70,648)	(132,515)
Net unrealized gains arising during period	75,368	42,367
Amounts reclassified from accumulated other comprehensive income	20,862	19,500
Net current period other comprehensive (loss) income	96,230	61,867
Stockholders' equity	25,582	(70,648)	(132,515)
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Stockholders' equity	12,263	(126,723)
Net unrealized gains arising during period	3,289	166,262
Amounts reclassified from accumulated other comprehensive income	(5,776)	(27,276)
Net current period other comprehensive (loss) income	(2,487)	138,986	108,464
Stockholders' equity	$ 9,776	$ 12,263	$ (126,723)