Fair Value Measurements - Schedule of assets and liabilities measured at fair value on recurring basis (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Securities available for sale, at fair value	$ 26,213	$ 28,344
Commercial mortgage backed securities issued by U.S. Agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Securities available for sale, at fair value	8,953	9,229
Residential mortgage backed securities issued by U.S. agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Securities available for sale, at fair value	17,260	19,115
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Securities available for sale, at fair value	26,213	28,344
Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Securities available for sale, at fair value	0	0
Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Securities available for sale, at fair value	26,213	28,344
Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Securities available for sale, at fair value	0	0
Recurring | Commercial mortgage backed securities issued by U.S. Agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Securities available for sale, at fair value	8,953	9,229
Recurring | Commercial mortgage backed securities issued by U.S. Agencies | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Securities available for sale, at fair value	0	0
Recurring | Commercial mortgage backed securities issued by U.S. Agencies | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Securities available for sale, at fair value	8,953	9,229
Recurring | Commercial mortgage backed securities issued by U.S. Agencies | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Securities available for sale, at fair value	0	0
Recurring | Residential mortgage backed securities issued by U.S. agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Securities available for sale, at fair value	17,260	19,115
Recurring | Residential mortgage backed securities issued by U.S. agencies | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Securities available for sale, at fair value	0	0
Recurring | Residential mortgage backed securities issued by U.S. agencies | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Securities available for sale, at fair value	17,260	19,115
Recurring | Residential mortgage backed securities issued by U.S. agencies | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Securities available for sale, at fair value	$ 0	$ 0