Securities Available-for-Sale - Continuous Unrealized Loss Position for 12 Months or Less and 12 Months and Longer (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	$ 93,238	$ 41,108
Less Than 12 Months, Unrealized Losses	276	80
12 Months or Longer, Fair Value	53,573	93,047
12 Months or Longer, Unrealized Losses	291	547
Total, Fair Value	146,811	134,155
Total, Unrealized Losses	567	627
U.S. Treasury [Member]
Schedule of Available-for-sale Securities [Line Items]
12 Months or Longer, Fair Value		1,992
12 Months or Longer, Unrealized Losses		8
Total, Fair Value		1,992
Total, Unrealized Losses		8
U.S. Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value		3,914
Less Than 12 Months, Unrealized Losses		31
Total, Fair Value		3,914
Total, Unrealized Losses		31
SBA Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	11,133	17,950
Less Than 12 Months, Unrealized Losses	11	28
12 Months or Longer, Fair Value	24,944	44,323
12 Months or Longer, Unrealized Losses	90	256
Total, Fair Value	36,077	62,273
Total, Unrealized Losses	101	284
U.S. Government Agency and Sponsored Enterprises Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	81,305	19,244
Less Than 12 Months, Unrealized Losses	264	21
12 Months or Longer, Fair Value	27,872	45,782
12 Months or Longer, Unrealized Losses	175	229
Total, Fair Value	109,177	65,026
Total, Unrealized Losses	439	250
Privately Issued Residential Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
12 Months or Longer, Fair Value	282	495
12 Months or Longer, Unrealized Losses	1	10
Total, Fair Value	282	495
Total, Unrealized Losses	1	10
Other Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	800
Less Than 12 Months, Unrealized Losses	1
12 Months or Longer, Fair Value	475	455
12 Months or Longer, Unrealized Losses	25	44
Total, Fair Value	1,275	455
Total, Unrealized Losses	$ 26	$ 44