Fair Value of Financial Instruments (Significant Observable Inputs used in the Valuation of Privately held Securities and Credit Default Assets) (Details) (USD $) In Thousands, unless otherwise specified					12 Months Ended					12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014 Significant unobservable inputs	Dec. 31, 2013 Significant unobservable inputs	Dec. 31, 2012 Significant unobservable inputs Privately held equity securities Discounted cash flow Minimum	Dec. 31, 2012 Significant unobservable inputs Privately held equity securities Discounted cash flow Maximum	Dec. 31, 2012 Significant unobservable inputs Privately held equity securities Discounted cash flow Weighted average	Mar. 31, 2014 Significant unobservable inputs Tax-exempt municipal Discounted cash flow	Dec. 31, 2013 Significant unobservable inputs Tax-exempt municipal Discounted cash flow	Dec. 31, 2013 Significant unobservable inputs Tax-exempt municipal Discounted cash flow Minimum	Dec. 31, 2012 Significant unobservable inputs Tax-exempt municipal Discounted cash flow Minimum	Dec. 31, 2013 Significant unobservable inputs Tax-exempt municipal Discounted cash flow Maximum	Dec. 31, 2012 Significant unobservable inputs Tax-exempt municipal Discounted cash flow Maximum	Dec. 31, 2012 Significant unobservable inputs Credit Default Swap Market comparable approach Minimum	Dec. 31, 2012 Significant unobservable inputs Credit Default Swap Market comparable approach Maximum	Dec. 31, 2012 Significant unobservable inputs Credit Default Swap Market comparable approach Weighted average
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Trading securities	$ 32,834	$ 35,991						$ 179	$ 274
Derivative assets		52
Total			179	274
Swap rate					0.239%	0.30%	0.27%
CMBS spread							34.50%
Expected term					1 year	4 years 9 months 15 days	2 years 10 months 24 days
Expected qtrly cash flow streams					$ 52	$ 1,574	$ 147
Short and long term cash flows										0.6294%	0.8435%	33.73%	37.469%
Offered quote														88.28%	96.66%	93.71%