Derivatives and hedging - Schedule of Fair Values of Derivative Assets and Liabilities in Condensed Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Derivative Assets
Fair Value	$ 0	$ 258
Less: Legally enforceable master netting agreements	0	0
Total derivatives, net	0	258
Derivative Liabilities
Fair Value	663	0
Less: Legally enforceable master netting agreements	0	0
Total derivatives, net	663	0
Interest rate swaps
Derivative Assets
Notional Amount	0	525,000
Fair Value	0	258
Derivative Liabilities
Notional Amount	400,000	0
Fair Value	$ 663	$ 0

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