Acquisition - Pro Forma Financial Information (Details) - MBT $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) $ / shares
Business Acquisition [Line Items]
Total revenue (net interest income plus other income) | $	$ 474,891
Net income | $	$ 161,228
Basic (in dollars per share) | $ / shares	$ 2.89
Diluted (in dollars per share) | $ / shares	$ 2.88