Variable Interest Entities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Rabbi Trusts [Member]
Variable Interest Entity [Line Items]
Carrying value of VIE assets and liabilities, net	$ 10,700	$ 11,300
Low Income Housing Tax Credit Partnerships [Member]
Variable Interest Entity [Line Items]
Carrying value of VIE assets and liabilities, net	18,900	10,900
Equity method investments	29,300	29,100
Commitments to fund equity investments	$ 12,200	3,600
Historic Rehabilitation Partnerships [Member]
Variable Interest Entity [Line Items]
Carrying value of VIE assets and liabilities, net		$ 350