Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 14,311	$ 24,393	$ 29,242	$ 55,283
Unrealized gains and losses on available for sale debt securities:
Net unrealized (losses) gains arising during the period	(930)	9,662	15,816	17,240
Reclassification adjustment for gains included in net income	0	0	0	0
Total	(930)	9,662	15,816	17,240
Unrealized losses on derivatives	(1,284)	(636)	(6,997)	(950)
Amortization related to post-retirement obligations	70	34	154	22
Total other comprehensive (loss) income	(2,144)	9,060	8,973	16,312
Total comprehensive income	$ 12,167	$ 33,453	$ 38,215	$ 71,595