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	Sep. 30, 2016	Dec. 31, 2015
Fair Value
Less than 12 Months	$ 32,011	$ 90,954
12 Months or Longer	0	2,101
Total	32,011	93,055
Gross Unrealized Losses
Less than 12 Months	341	505
12 Months or Longer	0	73
Total	341	578
Fair Value
Less than 12 Months	22,410	69,641
12 Months or Longer		14,888
Total	22,410	84,529
Gross Unrealized Losses
Less than 12 Months	65	519
12 Months or Longer		283
Total	65	802
Available-for-sale Securities and Held-to-maturity Securities [Abstract]
Less than 12 Months, Fair Value	54,421	160,595
12 Months or Longer, Fair Value	0	16,989
Total, Fair Value	54,421	177,584
Less than 12 Months, Gross Unrealized Losses	406	1,024
12 Months or Longer, Gross Unrealized Losses	0	356
Total, Gross Unrealized Losses	406	1,380
State and municipal
Fair Value
Less than 12 Months	22,468	7,558
12 Months or Longer
Total	22,468	7,558
Gross Unrealized Losses
Less than 12 Months	324	60
12 Months or Longer
Total	324	60
U.S. Government-sponsored mortgage-backed securities
Fair Value
Less than 12 Months	9,543	83,396
12 Months or Longer		2,101
Total	9,543	85,497
Gross Unrealized Losses
Less than 12 Months	17	445
12 Months or Longer		73
Total	17	518
Federal agencies
Fair Value
Less than 12 Months	15,469
12 Months or Longer
Total	15,469
Gross Unrealized Losses
Less than 12 Months	51
12 Months or Longer
Total	51
State and municipal
Fair Value
Less than 12 Months	6,941
12 Months or Longer		1,982
Total	6,941	1,982
Gross Unrealized Losses
Less than 12 Months	14
12 Months or Longer		15
Total	$ 14	15
U.S. Government-sponsored mortgage-backed securities
Fair Value
Less than 12 Months		69,641
12 Months or Longer		12,906
Total		82,547
Gross Unrealized Losses
Less than 12 Months		519
12 Months or Longer		268
Total		$ 787