Variable Interest Entities (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Rabbi Trusts [Member]
Variable Interest Entity [Line Items]
Carrying value of VIE assets and liabilities, net	$ 11,200	$ 10,000
Low Income Housing Tax Credit Partnerships [Member]
Variable Interest Entity [Line Items]
Carrying value of VIE assets and liabilities, net	8,500	10,600
Equity method investments	28,800	28,800
Historic Rehabilitation Partnerships [Member]
Variable Interest Entity [Line Items]
Carrying value of VIE assets and liabilities, net	0	350
Equity method investments	$ 951	$ 8,000