Loans Acquired - Textual (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	$ 60,555	$ 47,614	$ 56,694	$ 42,086
Provision for loan losses	9,285	9,150
Loans acquired, net
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	1,312	407	$ 95	$ 418
Provision for loan losses	$ 2,464	$ 68