Mergers and acquisitions - Schedule of Recognized Identified Assets Acquired and Liabilities Assumed (Details) - Atlantic Capital Bank $ in Thousands	Apr. 05, 2019 USD ($)
Assets
Cash and cash equivalents(1)	$ 207,822
Loans, net of fair value adjustments	374,966
Premises and equipment	9,650
Operating lease right-of-use assets	4,133
Core deposit intangible	10,760
Accrued interest and other assets	1,271
Total assets	608,602
Liabilities
Non-interest bearing deposits	118,405
Interest-bearing checking	112,225
Money markey and savings	211,135
Interest-bearing deposits	147,112
Total deposits	588,877
Operating lease liabilities	9,572
Operating lease liabilities	4,133
Accrued expenses and other liabilities	626
Total liabilities	603,208
Net assets acquired	5,394
Deposit premium	36,790
Cash and equivalents received	$ 171,032