Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Tax Credit Carryforward [Line Items]
Discrete Income Tax Benefit	$ 0	$ 49,323
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	45,000	27,000	$ 21,300
Decrease in Unrecognized Tax Benefits is Reasonably Possible	4,300
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	2,500	1,400
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense, net of tax	1,100	(1,800)	(2,300)
Qualified Affordable Housing Project Investments, Commitment	53,000	52,000
Maximum Loss Exposure Amount, Affordable Housing VIEs	73,000
Amortization Method Qualified Affordable Housing Project Investments	71,000	59,000
Deferred State and Local Income Tax Expense (Benefit), Tax Law Changes		(2,000)	(2,400)
Internal Revenue Service (IRS) [Member]
Tax Credit Carryforward [Line Items]
Other Tax Expense (Benefit)	800	800	800
Operating Loss Carryforwards	12,300
State and Local Jurisdiction [Member]
Tax Credit Carryforward [Line Items]
Tax Credit Carryforward, Amount	8,100
Deferred Income Tax Benefit, Net Operating Loss Carryforward		$ 900	$ 2,900
Operating Loss Carryforwards	95,200
Minimum | State and Local Jurisdiction [Member]
Tax Credit Carryforward [Line Items]
Decrease in Unrecognized Tax Benefits is Reasonably Possible	0
Maximum [Member] | State and Local Jurisdiction [Member]
Tax Credit Carryforward [Line Items]
Decrease in Unrecognized Tax Benefits is Reasonably Possible	$ 41,600