Stockholders' Equity Recon of Outstanding Common Stock table & Text (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Class of Stock [Line Items]
Shares of common stock repurchased		(66,475)	(232,837)	(3,511)
Purchase of common stock		$ (4,577)	$ (15,907)	$ (246)
Stock Repurchase Program, Remaining Authorized Repurchase Amount		$ 36,300
Common stock, shares outstanding		24,664,215	24,718,815	24,930,526	24,893,955
Stock Issued During Period, Shares, Stock-based Compensation, Net of Forfeitures		11,875	21,126	40,082
Stock-based compensation		$ 419	$ 499	$ 708
Preferred Stock, Liquidation Preference Per Share		$ 0.60
Preferred Stock, Redemption Price Per Share		$ 0.60
Parent Company
Class of Stock [Line Items]
Sale of Stock, Percentage of Ownership after Transaction		71.50%
Common Class A
Class of Stock [Line Items]
Shares of common stock repurchased		(66,475)	(232,837)	(3,511)
Common stock, shares outstanding		24,652,802	24,707,402	24,919,113	24,882,542
Common stock, without par value		$ 152,661	$ 152,652
Stock Issued During Period, Shares, Stock-based Compensation, Net of Forfeitures		11,875	21,126	40,082
Board of directors members		four to ten
Common Class B
Class of Stock [Line Items]
Shares of common stock repurchased		0	0	0
Common stock, shares outstanding	[1]	11,413	11,413	11,413	11,413
Common stock, without par value		$ 72	$ 72
Stock Issued During Period, Shares, Stock-based Compensation, Net of Forfeitures		0	0	0
Board of directors members		five to seven
Common stocks
Class of Stock [Line Items]
Purchase of common stock		$ (410)	$ (1,436)	$ (22)
Common stock, without par value		152,733	152,724	153,661	$ 152,975
Stock-based compensation		419	499	708
Common stocks | Common Class A
Class of Stock [Line Items]
Purchase of common stock		(410)	(1,436)	(22)
Common stock, without par value		152,661	152,652	153,589	152,903
Stock-based compensation		419	499	708
Common stocks | Common Class B
Class of Stock [Line Items]
Purchase of common stock		0	0	0
Common stock, without par value	[1]	72	72	72	$ 72
Stock-based compensation		$ 0	$ 0	$ 0

[1] There is no established market for our Class B common stock, although it is convertible upon demand of the holder into Class A common stock on a share-for-share basis.