Acquisitions - Pro Forma Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Business Combinations [Abstract]
Net interest and other income	$ 87,969	$ 86,694	$ 85,210	$ 174,663	$ 163,050
Net income	$ 27,303	$ 28,002	$ 17,710	$ 55,305	$ 31,481
Basic earnings per share (in dollars per share)	$ 0.59	$ 0.61	$ 0.39	$ 1.20	$ 0.69
Diluted earnings per share (in dollars per share)	$ 0.58	$ 0.60	$ 0.38	$ 1.18	$ 0.68