Equity (Details) (USD $) In Thousands, except Share data, unless otherwise specified	1 Months Ended	3 Months Ended	6 Months Ended		12 Months Ended
	Feb. 28, 2011	Mar. 31, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Equity (Textual)
Common stock issued in connection with business	372,992	372,992
Net of acquired cash, shares	368,527
Shares of common stock issued to trustee under 401(k) savings and retirement plan			0	110,881	110,881
Net proceeds from issuance of common stock to the trustee under 401(k) savings and retirement plan			$ 0	$ 4,745,000	$ 4,745,000
Number of shares held in treasury
Shares remaining under the current authorization repurchase program			3,411,416