Fair Value - Assets Measured at Fair Value on Recurring Basis (Detail) - USD ($)	Jun. 30, 2017	Dec. 31, 2016
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities measure at fair value on recurring basis	$ 29,668	$ 52,690
Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities measure at fair value on recurring basis	29,668	52,690
U.S. Government and Federal Agencies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities measure at fair value on recurring basis	24,658	41,559
U.S. Government and Federal Agencies | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities measure at fair value on recurring basis	24,658	41,559
Certificates of Deposit
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities measure at fair value on recurring basis		500
Certificates of Deposit | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities measure at fair value on recurring basis		500
FHLMC Certificates
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities measure at fair value on recurring basis		216
FHLMC Certificates | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities measure at fair value on recurring basis		216
FNMA Certificates
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities measure at fair value on recurring basis	1,301	3,606
FNMA Certificates | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities measure at fair value on recurring basis	1,301	3,606
GNMA Certificates
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities measure at fair value on recurring basis	3,709	6,809
GNMA Certificates | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities measure at fair value on recurring basis	$ 3,709	$ 6,809