Shareholders' Equity (Details)	1 Months Ended	12 Months Ended
	May 31, 1986 item	Dec. 31, 2012 item	Mar. 31, 1989
Shareholders' Equity
Number of Preferred Stock Purchase Right (the "Rights") for each outstanding share of the entity's common stock			1
Percentage of common stock to be acquired for rights to be exercisable		25.00%
Percentage of voting power to be acquired for rights to be exercisable		40.00%
Percentage of discount at which rights holders may purchase the Company's common stock on exercise of rights		50.00%
Percentage of discount at which rights holders may purchase the acquirer's shares in case of merger or other business combination		50.00%
Number of votes per share	5
Number of votes per share that the holder is entitled for shares acquired after May 30, 1986		1
Number of years shares purchased after May 30, 1986 must be held to be entitled to five votes per share		4 years
Number of votes per share after holding shares purchased after May 30, 1986 for four years		5