Income Tax - Income Tax Expense Differs from Computed Income Tax at Statutory Rates (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Income Tax Disclosure [Abstract]
Computed income tax at statutory rates			$ 34,513	$ 17,602
Differences in tax rates due to multiple jurisdictions			960	1,149
Effect of income subject to tax-exemption grant			(23,863)	(12,050)
Unrecognized tax (benefit) expense			(3,580)	193
Excess tax benefits on share-based compensation	$ (976)	$ 0
Other, net			286	2,144
Income tax expense	$ 2,632	$ 4,520	$ 7,340	$ 9,038