Net Income Per Share - Reconciliation of Basic and Diluted Net Income Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Net income available to common stockholders									$ 148,600	$ 164,460	$ 159,139
Net income available to common stockholders									$ 148,600	$ 164,460	$ 159,139
Weighted-Average Shares
Net income available to common stockholders (in shares)	53,899,501	53,843,508	53,762,913	54,732,073	55,348,176	51,433,227	49,432,167	49,369,024	54,058,471	51,412,133	49,262,015
Effect of dilutive stock options and warrants (in shares)									161,913	149,105	208,908
Net income available to common stockholders (in shares)	54,049,574	53,970,598	53,942,567	54,917,760	55,519,953	51,569,557	49,549,887	49,540,844	54,220,384	51,561,238	49,470,923
Basic net income per share:
Net income available to common stockholders (in dollars per share)	$ 0.83	$ 0.67	$ 0.62	$ 0.63	$ 0.87	$ 0.71	$ 0.83	$ 0.79	$ 2.75	$ 3.20	$ 3.23
Diluted net income per share:
Net income available to common stockholders (in dollars per share)	$ 0.83	$ 0.67	$ 0.62	$ 0.62	$ 0.87	$ 0.71	$ 0.83	$ 0.78	$ 2.74	$ 3.19	$ 3.22