Earnings Per Share (Details) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2020 USD ($) $ / shares shares	Mar. 31, 2020 USD ($)	Jun. 30, 2019 USD ($) $ / shares shares	Mar. 31, 2019 USD ($)	Jun. 30, 2020 USD ($) item $ / shares shares	Jun. 30, 2019 USD ($) $ / shares shares
Anti-dilutive securities
Number of classes of common stock | item					2
Anti-dilutive securities excluded from the computation of diluted earnings per share (in shares)	120,000
Numerator
Net income available to common stockholders | $	$ 143,781		$ 124,034		$ 277,088	$ 262,128
Denominator
Weighted-average common shares outstanding	113,690,839		111,371,790		113,581,392	111,196,011
Basic earnings per share (in dollars per share) | $ / shares	$ 1.26		$ 1.11		$ 2.44	$ 2.36
Numerator
Net income | $	$ 147,625	$ 137,151	$ 128,305	$ 138,094	$ 284,776	$ 266,399
Preferred stock dividends | $	(3,844)		(4,271)		(7,688)	(4,271)
Net income available to common stockholders | $	$ 143,781		$ 124,034		$ 277,088	$ 262,128
Denominator
Number of shares used in basic computation	113,690,839		111,371,790		113,581,392	111,196,011
Weighted-average effect of dilutive securities (in shares)	82,288		1,435,233		259,537	1,402,612
Number of shares used in per share computation	113,773,127		112,807,023		113,840,929	112,598,623
Diluted net income per share (in dollars per share) | $ / shares	$ 1.26		$ 1.10		$ 2.43	$ 2.33
Restricted Stock Units
Anti-dilutive securities
Anti-dilutive securities excluded from the computation of diluted earnings per share (in shares)					1,032,305	976,613