Investment Securities - Investments' Gross Unrealized Losses and Fair Value Aggregated by Investment Category and Length of Time in Continuous Unrealized Loss Position (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 Months, Fair Value	$ 28,798	$ 3,442
Less than 12 Months, Unrealized Losses	314	20
12 Months or Longer, Fair Value	2,374	15,297
12 Months or Longer, Unrealized Losses	58	230
Total, Fair Value	31,172	18,739
Total, Gross Unrealized Losses	372	250
Held-to-maturity Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 Months, Fair Value	12,206	14,910
Less than 12 Months, Gross Unrealized Losses	118	178
12 Months or Longer, Fair Value	11,626	38,741
12 Months or Longer, Gross Unrealized Losses	106	430
Total, Fair Value	23,832	53,651
Total, Gross Unrealized Losses	224	608
Available-for-sale Securities and Held-to-maturity Securities [Abstract]
Less than 12 Months, Fair Value	41,004	18,352
Less than 12 Months, Gross Unrealized Losses	432	198
12 Months or Longer, Fair Value	14,000	54,038
12 Months or Longer, Gross Unrealized Losses	164	660
Total, Fair Value	55,004	72,390
Total, Gross Unrealized Losses	596	858
State and municipal
Held-to-maturity Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 Months, Fair Value	7,243	5,119
Less than 12 Months, Gross Unrealized Losses	76	96
12 Months or Longer, Fair Value		250
12 Months or Longer, Gross Unrealized Losses
Total, Fair Value	7,243	5,369
Total, Gross Unrealized Losses	76	96
U.S. Government-sponsored mortgage-backed securities
Held-to-maturity Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 Months, Fair Value	4,963	9,791
Less than 12 Months, Gross Unrealized Losses	42	82
12 Months or Longer, Fair Value	11,626	38,491
12 Months or Longer, Gross Unrealized Losses	106	430
Total, Fair Value	16,589	48,282
Total, Gross Unrealized Losses	148	512
State and municipal
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 Months, Fair Value	23,922	1,256
Less than 12 Months, Unrealized Losses	310	7
12 Months or Longer, Fair Value		9,850
12 Months or Longer, Unrealized Losses		116
Total, Fair Value	23,922	11,106
Total, Gross Unrealized Losses	310	123
U.S. Government-sponsored mortgage-backed securities
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 Months, Fair Value	4,876	2,186
Less than 12 Months, Unrealized Losses	4	13
12 Months or Longer, Fair Value	2,374	5,447
12 Months or Longer, Unrealized Losses	58	114
Total, Fair Value	7,250	7,633
Total, Gross Unrealized Losses	$ 62	$ 127