Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2017
Consolidated Statements Of Comprehensive Income [Abstract]
Net income	$ 224,543	$ 239,738
Other comprehensive income, net of tax:
Unrealized holding gain on investments, net of tax expense of $102		191
Comprehensive income	$ 224,543	$ 239,929