Earnings Per Share Calculation Basic Diluted Earnings Per Share Voting Non Voting Common Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Earnings Per Share Diluted Other Disclosures [Abstract]
Net earnings available to common shareholders	$ 256,838	$ 338,345
Common Stock [Member]
Earnings Per Share Diluted Other Disclosures [Abstract]
Weighted Average Number Of Shares Outstanding Basic	19,607,788	19,607,788
Percent Weighted Average Shares Outstanding Common Stock	10.00%	10.00%
Net earnings available to common shareholders	$ 0	$ 0
Voting Common Stock dividends declared	0	(9,804)
Non-Voting Common Stock dividends declared	(7,059)	0
Non-Voting Common Stock dividends declared	(249,779)	(328,541)
Undistributed earnings available to common stockholders, participating securities	$ 24,978	$ 32,854
Undistributed earnings per share, common stock	$ 1.27	$ 1.68
Dividends declared per share, distributed	0	0.50
Basic and diluted earnings per share Common Stock	$ 1.27	$ 2.18
Nonvoting Common Stock [Member]
Earnings Per Share Diluted Other Disclosures [Abstract]
Weighted Average Number Of Shares Outstanding Basic	176,470,092	176,470,092
Percent Weighted Average Shares Outstanding Common Stock	90.00%	90.00%
Net earnings available to common shareholders	$ 0	$ 0
Voting Common Stock dividends declared	0	(9,804)
Non-Voting Common Stock dividends declared	(7,059)	0
Non-Voting Common Stock dividends declared	(249,779)	(328,541)
Undistributed earnings available to common stockholders, participating securities	$ 224,801	$ 295,687
Undistributed earnings per share, common stock	$ 1.27	$ 1.68
Dividends declared per share, distributed	0.04	0
Basic and diluted earnings per share Common Stock	$ 1.31	$ 1.68
Nonvoting Common Stock [Member] | Common Stock [Member]
Earnings Per Share Diluted Other Disclosures [Abstract]
Weighted Average Number Of Shares Outstanding Basic	196,077,880	196,077,880