Acquisitions - Schedule of Acquired Loan Data (Details) - USD ($) $ in Thousands	Jul. 14, 2017	May 19, 2017
IAB
Business Acquisition [Line Items]
Fair Value of Acquired Loans at Acquisition Date, Acquired receivables subject to ASC 310-30	$ 4,838
Gross Contractual Amounts Receivable at Acquisition Date, Acquired receivables subject to ASC 310-30	14,131
Best Estimate at Acquisition Date of Contractual Cash Flows Not Expected to be Collected, Acquired receivables subject to ASC 310-30	8,352
Fair Value of Acquired Loans at Acquisition Date, Acquired receivables not subject to ASC 310-30	720,544
Gross Contractual Amounts Receivable at Acquisition Date, Acquired receivables not subject to ASC 310-30	864,613
Best Estimate at Acquisition Date of Contractual Cash Flows Not Expected to be Collected, Acquired receivables not subject to ASC 310-30	$ 9,786
Arlington Bank
Business Acquisition [Line Items]
Fair Value of Acquired Loans at Acquisition Date, Acquired receivables subject to ASC 310-30		$ 2,625
Gross Contractual Amounts Receivable at Acquisition Date, Acquired receivables subject to ASC 310-30		6,183
Best Estimate at Acquisition Date of Contractual Cash Flows Not Expected to be Collected, Acquired receivables subject to ASC 310-30		2,891
Fair Value of Acquired Loans at Acquisition Date, Acquired receivables not subject to ASC 310-30		222,055
Gross Contractual Amounts Receivable at Acquisition Date, Acquired receivables not subject to ASC 310-30		308,857
Best Estimate at Acquisition Date of Contractual Cash Flows Not Expected to be Collected, Acquired receivables not subject to ASC 310-30		$ 2,741