CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 41,301	$ 47,315
Other comprehensive (loss) income, net of tax
Unrealized gain (loss) on debt securities arising during the period	(142,401)	(30,968)
Change in retirement obligation	346	405
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	11	0
Other comprehensive income (loss)	(142,044)	(30,563)
Comprehensive income (loss)	$ (100,743)	$ 16,752