Income Taxes	3 Months Ended
	Mar. 31, 2022
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company uses the estimated annual effective tax rate method for calculating its tax provision in interim periods, which represents the Company's best estimate of the effective tax rate expected for the full year. The estimated annual effective tax rate typically differs from the U.S. statutory tax rate, primarily as a result of tax-exempt investment income and any discrete items recognized during the period. The Company's effective tax rates were 18.2% and 18.7% for the three months ended March 31, 2022 and 2021, respectively. The effective tax rates were lower than the federal statutory rate of 21% due primarily to the tax benefits from stock-based compensation and from income generated by certain tax-exempt investments.