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, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share [Abstract]
Net income available to common stockholders									$ 164,460	$ 159,139	$ 96,070
Net income available to common stockholders									$ 164,460	$ 159,139	$ 96,070
Weighted-Average Shares
Net income available to common stockholders (in shares)	55,348,176	51,433,227	49,432,167	49,369,024	49,314,276	49,286,945	49,252,580	49,192,647	51,412,133	49,262,015	45,181,221
Effect of dilutive stock options and warrants (in shares)									149,105	208,908	221,757
Net income available to common stockholders (in shares)	55,519,953	51,569,557	49,549,887	49,540,844	49,511,233	49,492,019	49,451,406	49,427,972	51,561,238	49,470,923	45,402,978
Basic net income per share:
Net income available to common stockholders (in dollars per share)	$ 0.87	$ 0.71	$ 0.83	$ 0.79	$ 0.85	$ 0.83	$ 0.80	$ 0.75	$ 3.20	$ 3.23	$ 2.13
Diluted net income per share:
Net income available to common stockholders (in dollars per share)	$ 0.87	$ 0.71	$ 0.83	$ 0.78	$ 0.85	$ 0.83	$ 0.80	$ 0.74	$ 3.19	$ 3.22	$ 2.12