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, 2020	Dec. 31, 2019
Pooled trust preferred securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	$ 0	$ 875
Sales	0	(770)
Unrealized adjustment to fair value	0	(105)
Discount accretion	0	0
Balance, end of period	0	0
Single-issuer trust preferred securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	2,400	2,400
Sales	(2,160)	0
Unrealized adjustment to fair value	(242)	(4)
Discount accretion	2	4
Balance, end of period	0	2,400
Auction rate securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	101,926	102,994
Sales	0	0
Unrealized adjustment to fair value	(3,720)	(1,068)
Discount accretion	0	0
Balance, end of period	$ 98,206	$ 101,926