Stockholders' Equity and Earnings Per Share (Authorized Capital Stock) (Details) shares in Thousands	12 Months Ended
	Dec. 31, 2020 $ / shares shares	Dec. 31, 2019 $ / shares shares
Class of Stock [Line Items]
Preferred stock, par value (in usd per share) | $ / shares	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	5,000	5,000
Preferred stock outstanding (in shares)	0	0
Treasury Stock (in shares)	365	365
Shares Outstanding Class A
Class of Stock [Line Items]
Common stock, par value (in usd per share) | $ / shares	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	70,000	70,000
Common stock, shares, issued (in shares)	10,006	9,805
Common stock issued during period (in shares)	170	169
Shares Outstanding Class B
Class of Stock [Line Items]
Common stock, par value (in usd per share) | $ / shares	$ 0.01	$ 0.01
Common stock, convertible conversion ratio	1	1
Common stock, shares authorized (in shares)	30,000	30,000
Common stock, shares, issued (in shares)	4,045	4,076
Class B Common converted to Class A Common (in shares)	31	345