Investment Securities Held to Maturity (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
Schedule of Held-to-maturity Securities [Line Items]
Held-to-Maturity	$ 317,632	$ 299,261	$ 251,456
Held-to-Maturity Securities, at Fair Value	322,335	302,305	259,562
Gross Unrealized Gains	5,316	4,786	8,140
Gross Unrealized Losses	613	1,742	34
Held-To-Maturity Securities, Pledged as Collateral	316,632	298,261	250,456
Maturities of Debt Securities at Amortized Cost
Within One Year	31,895
From 1 - 5 Years	122,675
From 5 - 10 Years	159,073
Over 10 Years	3,989
Maturities of Debt Securities, at Fair Value
Within One Year	31,941
From 1 - 5 Years	124,679
From 5 - 10 Years	161,622
Over 10 Years	4,093
Securities in a Continuous Loss Position, at Fair Value
Less than 12 Months	62,745	108,972	8,794
12 Months or Longer	5,112	5,111	173
Total	67,857	114,083	8,967
Number of Securities in a Continuous Loss Position, in number of securities	103	137	33
Unrealized Losses on Securities in a Continuous Loss Position
Less than 12 Months	572	1,683	34
12 Months or Longer	41	59	0
Total	613	1,742	34
State and Municipal Obligations [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-Maturity	190,847	198,206	198,858
Held-to-Maturity Securities, at Fair Value	195,524	202,390	206,141
Gross Unrealized Gains	5,042	4,762	7,317
Gross Unrealized Losses	365	578	34
Maturities of Debt Securities at Amortized Cost
Within One Year	31,895
From 1 - 5 Years	83,077
From 5 - 10 Years	72,886
Over 10 Years	2,989
Maturities of Debt Securities, at Fair Value
Within One Year	31,941
From 1 - 5 Years	85,023
From 5 - 10 Years	75,467
Over 10 Years	3,093
Securities in a Continuous Loss Position, at Fair Value
Less than 12 Months	19,696	23,633	8,794
12 Months or Longer	5,112	5,111	173
Total	24,808	28,744	8,967
Number of Securities in a Continuous Loss Position, in number of securities	86	101	33
Unrealized Losses on Securities in a Continuous Loss Position
Less than 12 Months	324	519	34
12 Months or Longer	41	59	0
Total	365	578	34
Mortgage-Backed Securities - Residential [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-Maturity	125,785	100,055	51,598
Held-to-Maturity Securities, at Fair Value	125,811	98,915	52,421
Gross Unrealized Gains	274	24	823
Gross Unrealized Losses	248	1,164	0
Maturities of Debt Securities at Amortized Cost
Within One Year	0
From 1 - 5 Years	39,598
From 5 - 10 Years	86,187
Over 10 Years	0
Maturities of Debt Securities, at Fair Value
Within One Year	0
From 1 - 5 Years	39,656
From 5 - 10 Years	86,155
Over 10 Years	0
Securities in a Continuous Loss Position, at Fair Value
Less than 12 Months	43,049	85,339	0
12 Months or Longer	0	0	0
Total	43,049	85,339	0
Number of Securities in a Continuous Loss Position, in number of securities	17	36	0
Unrealized Losses on Securities in a Continuous Loss Position
Less than 12 Months	248	1,164	0
12 Months or Longer	0	0	0
Total	248	1,164	0
Mortgage-Backed Securities - Residential [Member] | U.S. Government Agency Obligations [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-Maturity	4,800	4,900
Held-to-Maturity Securities, at Fair Value	4,800	4,700
Mortgage-Backed Securities - Residential [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-Maturity	121,000	95,200	51,600
Held-to-Maturity Securities, at Fair Value	121,000	94,200	52,400
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
12 Months or Longer	0	0	0
Total	$ 0	$ 0	$ 0