Net Income Per Share - Reconciliation of Basic and Diluted Net Income Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Net Income
Net income available to common stockholders	$ 32,992	$ 41,056	$ 67,255	$ 79,873
Diluted net income per share	$ 32,992	$ 41,056	$ 67,255	$ 79,873
Weighted-Average Shares
Net income available to common stockholders (in shares)	53,762,913	49,432,167	54,247,493	49,400,770
Effect of potentially dilutive stock options and restricted stock awards (in shares)	179,654	117,720	182,026	144,382
Diluted net income per share (in shares)	53,942,567	49,549,887	54,429,519	49,545,152
Per Share Amount
Net income available to common stockholders (in dollars per share)	$ 0.62	$ 0.83	$ 1.24	$ 1.62
Diluted net income per share (in dollars per share)	$ 0.62	$ 0.83	$ 1.24	$ 1.61