Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Earnings Per Share
Antidilutive common share equivalents excluded from computation of earnings per share amount (in shares)	0	0
Net Income (Numerator)
Basic earnings per share (in dollars)	$ 430,507	$ 187,340
Diluted earnings per share (in dollars)	$ 430,507	$ 187,340
Weighted Average Shares (Denominator)
Basic earnings per share (in shares)	211,015,000	213,254,000
Dilutive common share equivalents (in shares)	1,239,000	770,000
Diluted earnings per share (in shares)	212,254,000	214,024,000
Per Share Amount
Basic (in dollars per share)	$ 2.04	$ 0.88
Diluted (in dollars per share)	$ 2.03	$ 0.88