Commitments And Contingencies (Narrative) (Details) - USD ($)	1 Months Ended		6 Months Ended
	Jul. 31, 2017	Apr. 30, 2016	Jun. 30, 2017	Aug. 26, 2016	May 31, 2016
Derivative Litigation And James J. Cotter, Jr. Employment Arbitration [Member]
Commitments And Contingencies [Line Items]
Amount of damages claimed by plaintiff			$ 1,200,000
Coverage limit			10,000,000
The STOMP Arbitration [Member]
Commitments And Contingencies [Line Items]
Settlement awarded		$ 2,300,000
Litigation interest percent		4.00%
Litigation payment received			$ 1,100,000
Litigation final payment date			June 2019
Subsequent Event [Member] | The STOMP Arbitration [Member]
Commitments And Contingencies [Line Items]
Litigation payment received	$ 427,000
Class B [Member] | Derivative Litigation And James J. Cotter, Jr. Employment Arbitration [Member]
Commitments And Contingencies [Line Items]
Shares held by estate				100,000
Class B [Member] | Cotter Estate [Member] | Derivative Litigation And James J. Cotter, Jr. Employment Arbitration [Member]
Commitments And Contingencies [Line Items]
Shares held by estate					327,808
Class B [Member] | Cotter Trust [Member] | Derivative Litigation And James J. Cotter, Jr. Employment Arbitration [Member]
Commitments And Contingencies [Line Items]
Shares held by estate					696,080