Investment Securities - Summary of Unrealized Losses of Available-for-Sale Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, Securities with losses under 12 months, Fair Value	$ 163,437	$ 232,776
Available-for-sale, Securities with losses under 12 months, Gross Unrealized Loss	1,748	4,466
Available-for-sale, Securities with losses over 12 months, Fair Value	22,704	16,315
Available-for-sale, Securities with losses over 12 months, Gross Unrealized Loss	448	556
Available-for-sale, Total, Fair Value	186,141	249,091
Available-for-sale, Total, Gross Unrealized Loss	2,196	5,022
Obligations of state and political subdivisions
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, Securities with losses under 12 months, Fair Value	12,843	13,402
Available-for-sale, Securities with losses under 12 months, Gross Unrealized Loss	338	1,020
Available-for-sale, Securities with losses over 12 months, Fair Value	0	0
Available-for-sale, Securities with losses over 12 months, Gross Unrealized Loss	0	0
Available-for-sale, Total, Fair Value	12,843	13,402
Available-for-sale, Total, Gross Unrealized Loss	338	1,020
GSE mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, Securities with losses under 12 months, Fair Value	6,440	29,119
Available-for-sale, Securities with losses under 12 months, Gross Unrealized Loss	7	302
Available-for-sale, Securities with losses over 12 months, Fair Value	0	0
Available-for-sale, Securities with losses over 12 months, Gross Unrealized Loss	0	0
Available-for-sale, Total, Fair Value	6,440	29,119
Available-for-sale, Total, Gross Unrealized Loss	7	302
Collateralized mortgage obligations: residential
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, Securities with losses under 12 months, Fair Value	142,077	187,235
Available-for-sale, Securities with losses under 12 months, Gross Unrealized Loss	1,380	3,099
Available-for-sale, Securities with losses over 12 months, Fair Value	20,155	14,194
Available-for-sale, Securities with losses over 12 months, Gross Unrealized Loss	424	507
Available-for-sale, Total, Fair Value	162,232	201,429
Available-for-sale, Total, Gross Unrealized Loss	1,804	3,606
Collateralized mortgage obligations: commercial
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, Securities with losses under 12 months, Fair Value	0	961
Available-for-sale, Securities with losses under 12 months, Gross Unrealized Loss	0	4
Available-for-sale, Securities with losses over 12 months, Fair Value	2,549	2,121
Available-for-sale, Securities with losses over 12 months, Gross Unrealized Loss	24	49
Available-for-sale, Total, Fair Value	2,549	3,082
Available-for-sale, Total, Gross Unrealized Loss	24	53
Mutual funds
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, Securities with losses under 12 months, Fair Value	2,077	2,059
Available-for-sale, Securities with losses under 12 months, Gross Unrealized Loss	23	41
Available-for-sale, Securities with losses over 12 months, Fair Value	0	0
Available-for-sale, Securities with losses over 12 months, Gross Unrealized Loss	0	0
Available-for-sale, Total, Fair Value	2,077	2,059
Available-for-sale, Total, Gross Unrealized Loss	$ 23	$ 41