Acquired and Covered Loans - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Transfers and Servicing [Abstract]
Outstanding balance of PCI loans	$ 156,000		$ 175,200
Renewed non-purchased credit impaired loans	483,100		458,000
Certain Loans Acquired in Transfer Accounted for as Debt Securities Accretable Yield Movement Schedule [Line Items]
Accretion on acquired loans	4,201	$ 3,618
FDIC indemnification asset	1,800		$ 2,100
Acquired and covered receivables
Certain Loans Acquired in Transfer Accounted for as Debt Securities Accretable Yield Movement Schedule [Line Items]
Accretion on acquired loans	$ 6,400	$ 5,100