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 - Level 3 - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Pooled trust preferred securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	$ 875	$ 707
Realized adjustments to fair value		0
Unrealized adjustment to fair value	(105)	168
Sales	(770)
Discount accretion	0	0
Balance, end of period	0	875
Single-issuer trust preferred securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	2,400	3,050
Realized adjustments to fair value		71
Unrealized adjustment to fair value	(4)	221
Sales	0
Discount accretion	4	8
Balance, end of period	2,400	2,400
Auction rate securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	102,994	98,668
Realized adjustments to fair value		0
Unrealized adjustment to fair value	(1,068)	4,326
Sales	0
Discount accretion	0	0
Balance, end of period	$ 101,926	102,994
Call Option | Pooled trust preferred securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Settlements - calls		0
Call Option | Single-issuer trust preferred securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Settlements - calls		(950)
Call Option | Auction rate securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Settlements - calls		$ 0