Fair Value Measurements Changes in Assets and Liabilities Measured at Fair Value on a Recurring Basis Using Level 3 Inputs (Details) - Fair Value, Measurements, Recurring [Member] - Fair Value, Inputs, Level 3 [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Pooled Trust Preferred Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	$ 706	$ 4,088
Unrealized adjustment to fair value	0	190
(Premium amortization) discount accretion	0	2
Sales		3,079
Settlements - calls		(117)
Balance, end of period	706	1,084
Single-issuer Trust Preferred Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	2,630	3,820
Unrealized adjustment to fair value	(233)	(2)
(Premium amortization) discount accretion	3	2
Sales		0
Settlements - calls		0
Balance, end of period	2,400	3,820
Auction Rate Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	98,059	100,941
Unrealized adjustment to fair value	(832)	332
(Premium amortization) discount accretion	99	105
Sales		0
Settlements - calls		(2,446)
Balance, end of period	$ 97,326	$ 98,932