Stock-Based Compensation (Activity in the Stock Plan) (Details) - shares	1 Months Ended	3 Months Ended	111 Months Ended	159 Months Ended
	May 31, 2014	Mar. 31, 2018	Mar. 31, 2018	Mar. 31, 2018
Employee Stock Award Plan-2008
Authorized Shares Available for Future Award Grants
Beginning balance (in shares)		996,828	1,900,000
Additional shares authorized (in shares)	1,500,000	0	1,500,000
Number of awards granted (in shares)		(153,209)	(3,025,180)
Number of awards forfeited or expired (in shares)		12,162	480,961
Ending balance (in shares)		855,781	855,781	855,781
Employee Stock Award Plan-2008 | Options Awards
Authorized Shares Available for Future Award Grants
Number of option awards exercised (in shares)		89,057	1,174,952
Employee Stock Award Plan-2008 | Unrestricted Stock Awards
Authorized Shares Available for Future Award Grants
Number of awards granted (in shares)		0	(8,470)
Employee Stock Award Plan-2008 | Restricted Stock Awards
Authorized Shares Available for Future Award Grants
Number of restricted stock awards vested (in shares)		19,658	57,826
Director Plan - 2005
Authorized Shares Available for Future Award Grants
Beginning balance (in shares)		61,813		300,000
Number of awards granted (in shares)		0		(262,190)
Number of awards forfeited or expired (in shares)		0		24,003
Ending balance (in shares)		61,813	61,813	61,813
Director Plan - 2005 | Options Awards
Authorized Shares Available for Future Award Grants
Number of option awards exercised (in shares)		7,599		96,880
Number of restricted stock awards vested (in shares)		0		54,272