CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 113,330	$ 41,965
Unrealized gains and losses on available for sale securities
Net gains (losses) arising during the period	16,267	(21,197)
Less reclassification adjustment for net losses included in net income	26	532
Total	16,293	(20,665)
Unrealized gains and losses on derivatives (cash flow hedges)
Net (losses) gains on derivatives arising during the period	(382)	1,960
Less reclassification adjustment for net losses included in net income	208	1,036
Total	(174)	2,996
Defined benefit pension plan
Amortization of net loss	55	112
Total other comprehensive income (loss)	16,174	(17,557)
Total comprehensive income	$ 129,504	$ 24,408