Securities Available-for-Sale - Continuous Unrealized Loss Position for 12 Months or Less and 12 Months and Longer (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	$ 67,027	$ 41,108
Less Than 12 Months, Unrealized Losses	442	80
12 Months or Longer, Fair Value	60,226	93,047
12 Months or Longer, Unrealized Losses	286	547
Total, Fair Value	127,253	134,155
Total, Unrealized Losses	728	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		17,950
Less Than 12 Months, Unrealized Losses		28
12 Months or Longer, Fair Value	30,790	44,323
12 Months or Longer, Unrealized Losses	54	256
Total, Fair Value	30,790	62,273
Total, Unrealized Losses	54	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	66,227	19,244
Less Than 12 Months, Unrealized Losses	441	21
12 Months or Longer, Fair Value	28,673	45,782
12 Months or Longer, Unrealized Losses	198	229
Total, Fair Value	94,900	65,026
Total, Unrealized Losses	639	250
Privately Issued Residential Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
12 Months or Longer, Fair Value	296	495
12 Months or Longer, Unrealized Losses	2	10
Total, Fair Value	296	495
Total, Unrealized Losses	2	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	467	455
12 Months or Longer, Unrealized Losses	32	44
Total, Fair Value	1,267	455
Total, Unrealized Losses	$ 33	$ 44