Noninterest Income - Lending Related Fees (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Lending related fees	$ 11,707	$ 10,675	$ 36,857	$ 30,938
Unused commitment fees
Accounts, Notes, Loans and Financing Receivable [Line Items]
Lending related fees	8,339	8,410	25,060	24,994
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Lending related fees	$ 3,368	$ 2,265	$ 11,797	$ 5,944