Fair Value Measurements (Details 2) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Assets:
Investment securities, available-for-sale	$ 832,700	$ 880,764
Trading account securities	192	146
Mortgages held for sale	6,079	10,879
Liabilities:
Accrued expenses and other liabilities	128,324	117,920
U.S. Treasury and Federal agencies securities
Assets:
Investment securities, available-for-sale	395,039	422,253
U.S. States and political subdivisions securities
Assets:
Investment securities, available-for-sale	123,239	105,437
Mortgage-backed securities - Federal agencies
Assets:
Investment securities, available-for-sale	275,080	312,407
Corporate debt securities
Assets:
Investment securities, available-for-sale	31,065	31,248
Foreign government and other securities
Assets:
Investment securities, available-for-sale	709	3,726
Total debt securities
Assets:
Investment securities, available-for-sale	825,132	875,071
Marketable equity securities
Assets:
Investment securities, available-for-sale	7,568	5,693
Recurring basis | Level 1
Assets:
Investment securities, available-for-sale	27,199	25,756
Trading account securities	192	146
Mortgages held for sale	0	0
Total	27,391	25,902
Liabilities:
Total	0	0
Recurring basis | Level 1 | Interest Rate swaps
Assets:
Accrued income and other assets	0	0
Liabilities:
Accrued expenses and other liabilities	0	0
Recurring basis | Level 1 | U.S. Treasury and Federal agencies securities
Assets:
Investment securities, available-for-sale	19,631	20,063
Recurring basis | Level 1 | U.S. States and political subdivisions securities
Assets:
Investment securities, available-for-sale	0	0
Recurring basis | Level 1 | Mortgage-backed securities - Federal agencies
Assets:
Investment securities, available-for-sale	0	0
Recurring basis | Level 1 | Corporate debt securities
Assets:
Investment securities, available-for-sale	0	0
Recurring basis | Level 1 | Foreign government and other securities
Assets:
Investment securities, available-for-sale	0	0
Recurring basis | Level 1 | Total debt securities
Assets:
Investment securities, available-for-sale	19,631	20,063
Recurring basis | Level 1 | Marketable equity securities
Assets:
Investment securities, available-for-sale	7,568	5,693
Recurring basis | Level 2
Assets:
Investment securities, available-for-sale	800,003	847,307
Trading account securities	0	0
Mortgages held for sale	6,079	10,879
Total	815,976	874,312
Liabilities:
Total	10,087	16,444
Recurring basis | Level 2 | Interest Rate swaps
Assets:
Accrued income and other assets	9,894	16,126
Liabilities:
Accrued expenses and other liabilities	10,087	16,444
Recurring basis | Level 2 | U.S. Treasury and Federal agencies securities
Assets:
Investment securities, available-for-sale	375,408	402,190
Recurring basis | Level 2 | U.S. States and political subdivisions securities
Assets:
Investment securities, available-for-sale	117,741	97,736
Recurring basis | Level 2 | Mortgage-backed securities - Federal agencies
Assets:
Investment securities, available-for-sale	275,080	312,407
Recurring basis | Level 2 | Corporate debt securities
Assets:
Investment securities, available-for-sale	31,065	31,248
Recurring basis | Level 2 | Foreign government and other securities
Assets:
Investment securities, available-for-sale	709	3,726
Recurring basis | Level 2 | Total debt securities
Assets:
Investment securities, available-for-sale	800,003	847,307
Recurring basis | Level 2 | Marketable equity securities
Assets:
Investment securities, available-for-sale	0	0
Recurring basis | Level 3
Assets:
Investment securities, available-for-sale	5,498	7,701
Trading account securities	0	0
Mortgages held for sale	0	0
Total	5,498	7,701
Liabilities:
Total	0	0
Recurring basis | Level 3 | Interest Rate swaps
Assets:
Accrued income and other assets	0	0
Liabilities:
Accrued expenses and other liabilities	0	0
Recurring basis | Level 3 | U.S. Treasury and Federal agencies securities
Assets:
Investment securities, available-for-sale	0	0
Recurring basis | Level 3 | U.S. States and political subdivisions securities
Assets:
Investment securities, available-for-sale	5,498	7,701
Recurring basis | Level 3 | Mortgage-backed securities - Federal agencies
Assets:
Investment securities, available-for-sale	0	0
Recurring basis | Level 3 | Corporate debt securities
Assets:
Investment securities, available-for-sale	0	0
Recurring basis | Level 3 | Foreign government and other securities
Assets:
Investment securities, available-for-sale	0	0
Recurring basis | Level 3 | Total debt securities
Assets:
Investment securities, available-for-sale	5,498	7,701
Recurring basis | Level 3 | Marketable equity securities
Assets:
Investment securities, available-for-sale	0	0
Recurring basis | Total
Assets:
Investment securities, available-for-sale	832,700	880,764
Trading account securities	192	146
Mortgages held for sale	6,079	10,879
Total	848,865	907,915
Liabilities:
Total	10,087	16,444
Recurring basis | Total | Interest Rate swaps
Assets:
Accrued income and other assets	9,894	16,126
Liabilities:
Accrued expenses and other liabilities	10,087	16,444
Recurring basis | Total | U.S. Treasury and Federal agencies securities
Assets:
Investment securities, available-for-sale	395,039	422,253
Recurring basis | Total | U.S. States and political subdivisions securities
Assets:
Investment securities, available-for-sale	123,239	105,437
Recurring basis | Total | Mortgage-backed securities - Federal agencies
Assets:
Investment securities, available-for-sale	275,080	312,407
Recurring basis | Total | Corporate debt securities
Assets:
Investment securities, available-for-sale	31,065	31,248
Recurring basis | Total | Foreign government and other securities
Assets:
Investment securities, available-for-sale	709	3,726
Recurring basis | Total | Total debt securities
Assets:
Investment securities, available-for-sale	825,132	875,071
Recurring basis | Total | Marketable equity securities
Assets:
Investment securities, available-for-sale	$ 7,568	$ 5,693