Significant Accounting Policies - Impact of new financial accounting standards (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Jan. 01, 2020	Dec. 31, 2019
Recently Issued Accounting Standards
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]		true
Cumulative Effect of New Accounting Principle in Period of Adoption	$ (15,922)
Right of use asset	8,511		$ 9,490
Lease liability	$ 8,601		$ 9,552
Allowance for credit losses on loans
Recently Issued Accounting Standards
Cumulative Effect of New Accounting Principle in Period of Adoption		$ 12,000
Post ASC 326
Recently Issued Accounting Standards
Cumulative Effect of New Accounting Principle in Period of Adoption		(15,900)
Post ASC 326 | Reserve for off-balance-sheet credit exposures
Recently Issued Accounting Standards
Cumulative Effect of New Accounting Principle in Period of Adoption		$ 3,900