CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME/ (LOSS) - UNAUDITED - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Comprehensive Income [Abstract]
Net income	$ 20,372	$ 51,253
Investments available-for-sale:
Net change in unrealized gains/ (losses) on investments available-for-sale	(7,703)	20,784
Related income tax (expense)/ benefit	1,954	(5,294)
Net investment gains reclassified into earnings	0	0
Related income tax expense	0	0
Net effect on other comprehensive income/ (loss)	(5,749)	15,490
Investments held-to-maturity:
Amortization of unrealized loss transferred from investments available-for-sale	371	405
Related income tax benefit	(94)	(103)
Net effect on other comprehensive income/ (loss)	277	302
Defined benefit pension plan:
Amortization of net loss	0	225
Related income tax benefit	0	(57)
Net effect on other comprehensive income/ (loss)	0	168
Total other comprehensive income/ (loss)	(5,472)	15,960
Comprehensive income	$ 14,900	$ 67,213