Noninterest Income - Lending Related Fees (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Lending related fees	$ 11,213	$ 9,528	$ 25,150	$ 20,263
Unused commitment fees
Accounts, Notes, Loans and Financing Receivable [Line Items]
Lending related fees	7,051	7,827	16,721	16,584
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Lending related fees	$ 4,162	$ 1,701	$ 8,429	$ 3,679