Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 2,008	$ 45,110
Securities available for sale:
Unrealized holding gains on securities	16,694	11,317
Reclassification adjustment for losses realized in net income	0	(10)
Total securities	16,694	11,307
Derivative instruments:
Unrealized holding losses on derivative instruments	(3,003)	(915)
Total derivative instruments	(3,003)	(915)
Defined benefit pension and post-retirement benefit plans:
Amortization of net actuarial loss recognized in net periodic pension cost	46	54
Total defined benefit pension and post-retirement benefit plans	(46)	(54)
Other comprehensive income, net of tax	13,737	10,446
Comprehensive income	$ 15,745	$ 55,556