Net income per common share - Computation of net income (loss) per common share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Earnings Per Share
Net income	$ 103,283	$ 158,979
Preferred stock dividends	(353)	(353)
Net income applicable to common stock	$ 102,930	$ 158,626
Average common shares outstanding	71,869,735	71,541,778
Average potential dilutive common shares	97,068	64,418
Average common shares outstanding - assuming dilution	71,966,803	71,606,196
Basic EPS	$ 1.43	$ 2.22
Diluted EPS	$ 1.43	$ 2.22