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	Jun. 30, 2016	Dec. 31, 2015
Fair Value
Less than 12 Months	$ 4,007	$ 90,954
12 Months or Longer	1,053	2,101
Total	5,060	93,055
Gross Unrealized Losses
Less than 12 Months	15	505
12 Months or Longer	5	73
Total	20	578
Fair Value
Less than 12 Months	4,995	69,641
12 Months or Longer		14,888
Total	4,995	84,529
Gross Unrealized Losses
Less than 12 Months	5	519
12 Months or Longer		283
Total	5	802
Available-for-sale Securities and Held-to-maturity Securities [Abstract]
Less than 12 Months, Fair Value	9,002	160,595
12 Months or Longer, Fair Value	1,053	16,989
Total, Fair Value	10,055	177,584
Less than 12 Months, Gross Unrealized Losses	20	1,024
12 Months or Longer, Gross Unrealized Losses	5	356
Total, Gross Unrealized Losses	25	1,380
State and municipal
Fair Value
Less than 12 Months		7,558
12 Months or Longer
Total		7,558
Gross Unrealized Losses
Less than 12 Months		60
12 Months or Longer
Total		60
U.S. Government-sponsored mortgage-backed securities
Fair Value
Less than 12 Months	4,007	83,396
12 Months or Longer	1,053	2,101
Total	5,060	85,497
Gross Unrealized Losses
Less than 12 Months	15	445
12 Months or Longer	5	73
Total	20	518
Federal agencies
Fair Value
Less than 12 Months	4,995
12 Months or Longer
Total	4,995
Gross Unrealized Losses
Less than 12 Months	5
12 Months or Longer
Total	$ 5
State and municipal
Fair Value
Less than 12 Months
12 Months or Longer		1,982
Total		1,982
Gross Unrealized Losses
Less than 12 Months
12 Months or Longer		15
Total		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