Securities, Unrealized Gains (Losses) Related to Equity Securities (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) Issuer	Dec. 31, 2018 USD ($) Issuer
Gains and losses on equity securities [Abstract]
Net gains and losses recognized on equity securities	$ 4,280	$ 281
Less: Net gains and losses recognized during the period on equity securities sold during the period	3,966	555
Unrealized gains and losses recognized on equity securities still held	314	(274)
Equity Securities without Readily Determinable Fair Value, Annual Amount [Abstract]
Impairment adjustments of equity securities without readily determinable fair values	0	0
Carrying amount of equity securities without readily determinable fair values	4,000	4,000
Downward adjustments of equity securities without readily determinable fair values	0	0
Upward adjustments of equity securities without readily determinable fair values	$ 0	$ 0
Number of issuers whose holdings exceeded 10% of consolidated stockholders' equity, excluding U.S. Government securities | Issuer	0	0
Visa Class B Common Stock [Member]
Equity Securities without Readily Determinable Fair Value, Annual Amount [Abstract]
Gain from sale of equity securities without readily determinable fair value	$ 4,000