Investment Securities Held to Maturity (Details) $ in Thousands	Jun. 30, 2016 USD ($)	Dec. 31, 2015 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)
Schedule of Held-to-maturity Securities [Line Items]
Held-to-Maturity	$ 343,814	$ 320,611	$ 324,116
Held-to-Maturity Securities, at Fair Value	354,778	325,930	328,361	$ 328,361
Gross Unrealized Gains	10,965	5,487	4,938
Gross Unrealized Losses	1	168	692
Held-To-Maturity Securities, Pledged as Collateral	327,820	299,767	300,040
Maturities of Debt Securities at Amortized Cost
Within One Year	35,656
From 1 - 5 Years	159,518
From 5 - 10 Years	143,454
Over 10 Years	5,186
Maturities of Debt Securities, at Fair Value
Within One Year	35,754
From 1 - 5 Years	165,148
From 5 - 10 Years	148,486
Over 10 Years	5,390
Securities in a Continuous Loss Position, at Fair Value
Less than 12 Months	0	8,302	0
12 Months or Longer	659	15,918	48,715
Total	$ 659	$ 24,220	$ 48,715
Number of Securities in a Continuous Loss Position, in number of securities	3	62	158
Unrealized Losses on Securities in a Continuous Loss Position
Less than 12 Months	$ 0	$ 104	$ 0
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	1	64	692
Total	1	168	692
State and Municipal Obligations [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-Maturity	257,982	226,053	219,878
Held-to-Maturity Securities, at Fair Value	265,983	230,621	223,031
Gross Unrealized Gains	8,002	4,619	3,737
Gross Unrealized Losses	1	51	583
Maturities of Debt Securities at Amortized Cost
Within One Year	35,656
From 1 - 5 Years	86,496
From 5 - 10 Years	131,644
Over 10 Years	4,186
Maturities of Debt Securities, at Fair Value
Within One Year	35,754
From 1 - 5 Years	89,653
From 5 - 10 Years	136,186
Over 10 Years	4,390
Securities in a Continuous Loss Position, at Fair Value
Less than 12 Months	0	2,302	0
12 Months or Longer	659	11,764	44,748
Total	$ 659	$ 14,066	$ 44,748
Number of Securities in a Continuous Loss Position, in number of securities	3	54	157
Unrealized Losses on Securities in a Continuous Loss Position
Less than 12 Months	$ 0	$ 11	$ 0
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	1	40	583
Total	1	51	583
Mortgage-Backed Securities - Residential [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-Maturity	84,832	93,558	103,238
Held-to-Maturity Securities, at Fair Value	87,795	94,309	104,330
Gross Unrealized Gains	2,963	868	1,201
Gross Unrealized Losses	0	117	109
Maturities of Debt Securities at Amortized Cost
Within One Year	0
From 1 - 5 Years	73,022
From 5 - 10 Years	11,810
Over 10 Years	0
Maturities of Debt Securities, at Fair Value
Within One Year	0
From 1 - 5 Years	75,495
From 5 - 10 Years	12,300
Over 10 Years	0
Securities in a Continuous Loss Position, at Fair Value
Less than 12 Months	0	6,000	0
12 Months or Longer	0	4,154	3,967
Total	$ 0	$ 10,154	$ 3,967
Number of Securities in a Continuous Loss Position, in number of securities	0	8	1
Unrealized Losses on Securities in a Continuous Loss Position
Less than 12 Months	$ 0	$ 93	$ 0
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	24	109
Total	0	117	109
Mortgage-Backed Securities - Residential [Member] | U.S. Government Agency Obligations [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-Maturity	3,497	3,800	28,800
Held-to-Maturity Securities, at Fair Value	3,622	3,940	29,000
Mortgage-Backed Securities - Residential [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-Maturity	81,335	89,758	74,500
Held-to-Maturity Securities, at Fair Value	84,173	90,469	75,400
Corporate and Other Debt Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-Maturity	1,000	1,000	1,000
Held-to-Maturity Securities, at Fair Value	1,000	1,000	1,000
Gross Unrealized Gains	0	0	0
Gross Unrealized Losses	0	0	0
Maturities of Debt Securities at Amortized Cost
Within One Year	0
From 1 - 5 Years	0
From 5 - 10 Years	0
Over 10 Years	1,000
Maturities of Debt Securities, at Fair Value
Within One Year	0
From 1 - 5 Years	0
From 5 - 10 Years	0
Over 10 Years	1,000
Securities in a Continuous Loss Position, at Fair Value
Less than 12 Months	0	0	0
12 Months or Longer	0	0	0
Total	$ 0	$ 0	$ 0
Number of Securities in a Continuous Loss Position, in number of securities	0	0	0
Unrealized Losses on Securities in a Continuous Loss Position
Less than 12 Months	$ 0	$ 0	$ 0
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0	0
Total	$ 0	$ 0	$ 0