Accumulated Other Comprehensive Income (Loss) - Reclassifications (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Reclassification Adjustments out of Accumulated Other Comprehensive Income [Line Items]
Other income - net realized gains on sales of available for sale securities	$ 581,000	$ 248,000
Interest expense - subordinated debentures and term loans	(1,641,000)	(725,000)
Other expenses - salaries and employee benefits	(25,301,000)	(20,791,000)
Income tax expense	(4,369,000)	(4,668,000)
NET INCOME	13,620,000	11,865,000
Amount Reclassified from Accumulated Other Comprehensive Income (Loss) for the Period
Reclassification Adjustments out of Accumulated Other Comprehensive Income [Line Items]
NET INCOME	154,000	(601,000)
Amount Reclassified from Accumulated Other Comprehensive Income (Loss) for the Period | Unrealized gains (losses) on available for sale securities
Reclassification Adjustments out of Accumulated Other Comprehensive Income [Line Items]
Other income - net realized gains on sales of available for sale securities	581,000	248,000
Income tax expense	(203,000)	(87,000)
NET INCOME	378,000	161,000
Amount Reclassified from Accumulated Other Comprehensive Income (Loss) for the Period | Unrealized gains (losses) on cash flow hedges
Reclassification Adjustments out of Accumulated Other Comprehensive Income [Line Items]
Interest expense - subordinated debentures and term loans	(344,000)	(188,000)
Income tax expense	120,000	66,000
NET INCOME	(224,000)	(122,000)
Amount Reclassified from Accumulated Other Comprehensive Income (Loss) for the Period | Unrealized gains (losses) on defined benefit plans
Reclassification Adjustments out of Accumulated Other Comprehensive Income [Line Items]
Other expenses - salaries and employee benefits		(985,000)
Income tax expense		345,000
NET INCOME	$ 0	$ (640,000)