Loans and Allowance for Loan Losses - Industry Classification System (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Lessors of nonresidential buildings
Accounts, Notes, Loans and Financing Receivable [Line Items]
Outstanding Principal Balances	$ 2,679,712
Unfunded Commitments	542,158
Total exposure	3,221,870	$ 1,701,853
Lessors of residential buildings
Accounts, Notes, Loans and Financing Receivable [Line Items]
Outstanding Principal Balances	879,787
Unfunded Commitments	289,682
Total exposure	$ 1,169,469	$ 874,234