Noninterest Income - Lending Related Fees (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Lending related fees	$ 13,937	$ 10,735
Unused commitment fees
Accounts, Notes, Loans and Financing Receivable [Line Items]
Lending related fees	9,670	8,757
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Lending related fees	$ 4,267	$ 1,978