Investment Securities Available for Sale (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Available-For-Sale Securities, at Amortized Cost	$ 469,621	$ 469,384	$ 456,176
Available-for-sale Securities, at Fair Value	478,775	478,698	466,785
Gross Unrealized Gains	9,528	9,843	10,979
Gross Unrealized Losses	374	529	370
Available-For-Sale Securities, Pledged as Collateral	274,433	260,292	304,303
Maturities of Debt Securities, at Amortized Cost
Within One Year	44,835
From 1 - 5 Years	406,401
From 5 - 10 Years	15,345
Over 10 Years	1,920
Maturities of Debt Securities at Fair Value
Within One Year	45,292
From 1 - 5 Years	414,340
From 5 - 10 Years	16,284
Over 10 Years	1,720
Securities in a Continuous Loss Position, at Fair Value
Less than 12 Months	134,689	137,839	17,875
12 Months or Longer	1,481	7,117	0
Total	136,170	144,956	17,875
Number of Securities in a Continuous Loss Position, in number of securities	194	238	13
Unrealized Losses on Securities in a Continuous Loss Position
Less than 12 Months	372	492	370
12 Months or Longer	2	37	0
Total	374	529	370
U.S. Agency Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-For-Sale Securities, at Amortized Cost	132,217	122,297	65,303
Available-for-sale Securities, at Fair Value	132,153	122,457	65,660
Gross Unrealized Gains	23	204	357
Gross Unrealized Losses	87	44	0
Maturities of Debt Securities, at Amortized Cost
Within One Year	0
From 1 - 5 Years	132,217
From 5 - 10 Years	0
Over 10 Years	0
Maturities of Debt Securities at Fair Value
Within One Year	0
From 1 - 5 Years	132,153
From 5 - 10 Years	0
Over 10 Years	0
Securities in a Continuous Loss Position, at Fair Value
Less than 12 Months	94,909	72,531	0
12 Months or Longer	0	0	0
Total	94,909	72,531	0
Number of Securities in a Continuous Loss Position, in number of securities	28	22	0
Unrealized Losses on Securities in a Continuous Loss Position
Less than 12 Months	87	44	0
12 Months or Longer	0	0	0
Total	87	44	0
U.S. Agency Obligations [Member] | Agency Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-For-Sale Securities, at Amortized Cost	132,200		65,300
Available-for-sale Securities, at Fair Value	132,200		65,700
State and Municipal Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-For-Sale Securities, at Amortized Cost	104,304	84,798	43,186
Available-for-sale Securities, at Fair Value	104,469	84,838	43,482
Gross Unrealized Gains	228	206	308
Gross Unrealized Losses	63	166	12
Maturities of Debt Securities, at Amortized Cost
Within One Year	29,880
From 1 - 5 Years	69,269
From 5 - 10 Years	4,235
Over 10 Years	920
Maturities of Debt Securities at Fair Value
Within One Year	29,925
From 1 - 5 Years	69,340
From 5 - 10 Years	4,284
Over 10 Years	920
Securities in a Continuous Loss Position, at Fair Value
Less than 12 Months	31,325	46,627	2,831
12 Months or Longer	1,481	2,149	0
Total	32,806	48,776	2,831
Number of Securities in a Continuous Loss Position, in number of securities	154	198	7
Unrealized Losses on Securities in a Continuous Loss Position
Less than 12 Months	61	160	12
12 Months or Longer	2	6	0
Total	63	166	12
Mortgage-Backed Securities - Residential [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-For-Sale Securities, at Amortized Cost	219,067	252,480	345,294
Available-for-sale Securities, at Fair Value	228,323	261,804	355,382
Gross Unrealized Gains	9,256	9,405	10,240
Gross Unrealized Losses	0	81	152
Maturities of Debt Securities, at Amortized Cost
Within One Year	14,955
From 1 - 5 Years	193,002
From 5 - 10 Years	11,110
Over 10 Years	0
Maturities of Debt Securities at Fair Value
Within One Year	15,367
From 1 - 5 Years	200,956
From 5 - 10 Years	12,000
Over 10 Years	0
Securities in a Continuous Loss Position, at Fair Value
Less than 12 Months	3	10,230	14,205
12 Months or Longer	0	4,968	0
Total	3	15,198	14,205
Number of Securities in a Continuous Loss Position, in number of securities	1	7	4
Unrealized Losses on Securities in a Continuous Loss Position
Less than 12 Months	0	50	152
12 Months or Longer	0	31	0
Total	0	81	152
Mortgage-Backed Securities - Residential [Member] | Agency Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-For-Sale Securities, at Amortized Cost	35,300		44,400
Available-for-sale Securities, at Fair Value	37,200		45,900
Mortgage-Backed Securities - Residential [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-For-Sale Securities, at Amortized Cost	183,800		300,900
Available-for-sale Securities, at Fair Value	191,100		309,500
Corporate and Other Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-For-Sale Securities, at Amortized Cost	12,913	8,689	1,028
Available-for-sale Securities, at Fair Value	12,691	8,451	828
Gross Unrealized Gains	2	0	0
Gross Unrealized Losses	224	238	200
Maturities of Debt Securities, at Amortized Cost
Within One Year	0
From 1 - 5 Years	11,913
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	11,891
From 5 - 10 Years	0
Over 10 Years	800
Securities in a Continuous Loss Position, at Fair Value
Less than 12 Months	8,452	8,451	800
12 Months or Longer	0	0	0
Total	8,452	8,451	800
Number of Securities in a Continuous Loss Position, in number of securities	11	11	1
Unrealized Losses on Securities in a Continuous Loss Position
Less than 12 Months	224	238	200
12 Months or Longer	0	0	0
Total	224	238	200
Mutual Funds and Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-For-Sale Securities, at Amortized Cost	1,120	1,120	1,365
Available-for-sale Securities, at Fair Value	1,139	1,148	1,433
Gross Unrealized Gains	19	28	74
Gross Unrealized Losses	0	0	6
Securities in a Continuous Loss Position, at Fair Value
Less than 12 Months	0	0	39
12 Months or Longer	0	0	0
Total	0	0	39
Number of Securities in a Continuous Loss Position, in number of securities	0	0	1
Unrealized Losses on Securities in a Continuous Loss Position
Less than 12 Months	0	0	6
12 Months or Longer	0	0	0
Total	$ 0	$ 0	$ 6