Fair Value Measurements (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Investments in securities that are classified as level 3
Available-for-sale Securities	387,038	348,554
Discounted cash flow methodology [Member] | Significant Unobservable Inputs (Level 3) | Weighted Average [Member]
Investments in securities that are classified as level 3
Cumulative Prepayment	6.90%	7.00%
Cumulative Default	13.30%	13.90%
Loss Given Default	95.90%	96.10%
Cure Given Default	39.20%	46.70%
Pooled trust preferred securities | Significant Unobservable Inputs (Level 3)
Investments in securities that are classified as level 3
Available-for-sale Securities	6,272	6,321
Pooled trust preferred securities | Discounted cash flow methodology [Member] | Significant Unobservable Inputs (Level 3) | Minimum [Member]
Investments in securities that are classified as level 3
Cumulative Prepayment	0.00%	0.00%
Cumulative Default	2.80%	3.00%
Loss Given Default	85.00%	85.00%
Cure Given Default	0.00%	0.00%
Pooled trust preferred securities | Discounted cash flow methodology [Member] | Significant Unobservable Inputs (Level 3) | Maximum [Member]
Investments in securities that are classified as level 3
Cumulative Prepayment	75.00%	75.00%
Cumulative Default	100.00%	100.00%
Loss Given Default	100.00%	100.00%
Cure Given Default	75.00%	75.00%
Impaired loans | Significant Unobservable Inputs (Level 3)
Investments in securities that are classified as level 3
Fair Value	7,559	8,196
Other real estate owned and other foreclosed assets | Significant Unobservable Inputs (Level 3)
Investments in securities that are classified as level 3
Fair Value	6,285	7,743