Shareholders' Equity (Details) (USD $)	0 Months Ended			1 Months Ended	3 Months Ended		12 Months Ended
	Aug. 21, 2012	Aug. 07, 2012	Nov. 01, 2011	Feb. 28, 2013	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Common stock repurchase, authorized amount			$ 15,000,000	$ 15,000,000
Stock repurchased during period, shares					199,000		639,000
Stock repurchased during period, aggregate purchase price					1,200,000		3,300,000
Common stock repurchase, remaining authorized amount					13,800,000
Retired shares of treasury stock		2,700,000
Retirement of treasury shares		15,100,000
Quarterly cash dividend per share of common stock outstanding approved	$ 0.025				$ 0.025
Dividend payment from cash on hand					687,000	0
Treasury Stock [Member]
Retirement of treasury shares		15,100,000
Common Stock [Member]
Retirement of treasury shares		27,000
Additional Paid-In Capital [Member]
Retirement of treasury shares		$ 15,100,000