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	Dec. 31, 2015	Dec. 31, 2014
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 Months, Fair Value	$ 90,954	$ 3,442
Less than 12 Months, Gross Unrealized Losses	505	20
12 Months or Longer, Fair Value	2,101	15,297
12 Months or Longer, Gross Unrealized Losses	73	230
Total, Fair Value	93,055	18,739
Total, Gross Unrealized Losses	578	250
Held-to-maturity Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 Months, Fair Value	69,641	14,910
Less than 12 Months, Gross Unrealized Losses	519	178
12 Months or Longer, Fair Value	14,888	38,741
12 Months or Longer, Gross Unrealized Losses	283	430
Total, Fair Value	84,529	53,651
Total, Gross Unrealized Losses	802	608
Available-for-sale Securities and Held-to-maturity Securities [Abstract]
Less than 12 Months, Fair Value	160,595	18,352
Less than 12 Months, Gross Unrealized Losses	1,024	198
12 Months or Longer, Fair Value	16,989	54,038
12 Months or Longer, Gross Unrealized Losses	356	660
Total, Fair Value	177,584	72,390
Total, Gross Unrealized Losses	1,380	858
State and municipal
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 Months, Fair Value	7,558	1,256
Less than 12 Months, Gross Unrealized Losses	$ 60	7
12 Months or Longer, Fair Value		9,850
12 Months or Longer, Gross Unrealized Losses		116
Total, Fair Value	$ 7,558	11,106
Total, Gross Unrealized Losses	60	123
U.S. Government-sponsored mortgage-backed securities
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 Months, Fair Value	83,396	2,186
Less than 12 Months, Gross Unrealized Losses	445	13
12 Months or Longer, Fair Value	2,101	5,447
12 Months or Longer, Gross Unrealized Losses	73	114
Total, Fair Value	85,497	7,633
Total, Gross Unrealized Losses	$ 518	127
State and municipal
Held-to-maturity Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 Months, Fair Value		5,119
Less than 12 Months, Gross Unrealized Losses		96
12 Months or Longer, Fair Value	$ 1,982	$ 250
12 Months or Longer, Gross Unrealized Losses	15
Total, Fair Value	1,982	$ 5,369
Total, Gross Unrealized Losses	15	96
U.S. Government-sponsored mortgage-backed securities
Held-to-maturity Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 Months, Fair Value	69,641	9,791
Less than 12 Months, Gross Unrealized Losses	519	82
12 Months or Longer, Fair Value	12,906	38,491
12 Months or Longer, Gross Unrealized Losses	268	430
Total, Fair Value	82,547	48,282
Total, Gross Unrealized Losses	$ 787	$ 512