Income Taxes (Narrative) (Details) - USD ($)	3 Months Ended	9 Months Ended		12 Months Ended
	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Operating Loss Carryforwards [Line Items]
Effective Income Tax Rate Reconciliation, Deduction, Amount				$ 945,000
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	2100.00%		3500.00%	21.00%	31.55%	35.00%
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount				$ (1,663,000)	$ 1,109,000	$ 41,000
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Amount					1,500,000
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent			2100.00%
Gross amounts of deferred tax assets	$ 81,846,000			90,403,000	81,846,000
Valuation allowance	(4,671,000)			(16,881,000)	(4,671,000)
Foreign subsidiary income				14,362,000	25,144,000	3,071,000
Cumulative undistributed earnings of foreign subsidiaries				114,000,000
Income Tax Effects Allocated Directly to Equity, Employee Stock Options				1,129,000	1,230,000
Amount accrued for the payment of interest and penalties				38,000	33,000
Federal
Operating Loss Carryforwards [Line Items]
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount			$ 16,128,000		16,102,000
Foreign net operating losses	$ 3,837,000			$ 2,372,000	$ 3,837,000	$ 4,370,000
Scenario, Adjustment [Member] | Federal
Operating Loss Carryforwards [Line Items]
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount		$ 26,000