Earnings Per Share ("EPS") (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings Per Share [Abstract]
Net income available to common stockholders	$ 74,911	$ 58,789	$ 142,318	$ 136,012
Average common shares outstanding (in shares)	108,362	108,982	108,286	110,936
Average potential dilutive common shares (in shares)	460	148	460	148
Average diluted common shares (in shares)	108,822	109,130	108,746	111,084
Basic earnings per share (in dollars per share)	$ 0.69	$ 0.54	$ 1.31	$ 1.23
Diluted earnings per share (in dollars per share)	$ 0.69	$ 0.54	$ 1.31	$ 1.22