Loans and Allowance for Loan Losses - Industry Classification System (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Outstanding Principal Balances	$ 5,969,494
Unfunded Commitments	2,266,833
Total exposure	8,236,327	$ 7,437,746
Lessors of Nonresidential Buildings
Accounts, Notes, Loans and Financing Receivable [Line Items]
Outstanding Principal Balances	3,681,897
Unfunded Commitments	896,219
Total exposure	4,578,116	3,932,059
Lessors of Residential Buildings and Dwellings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Outstanding Principal Balances	951,295
Unfunded Commitments	648,542
Total exposure	1,599,837	1,484,697
New housing for-sale builders
Accounts, Notes, Loans and Financing Receivable [Line Items]
Outstanding Principal Balances	530,345
Unfunded Commitments	560,258
Total exposure	1,090,603	1,100,989
Hotels and motels
Accounts, Notes, Loans and Financing Receivable [Line Items]
Outstanding Principal Balances	805,957
Unfunded Commitments	161,814
Total exposure	$ 967,771	$ 920,001