CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (Parenthetical)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares in connection with acquisitions (in shares)	19,685	35,714	498,730
Issuance of shares upon conversion of notes to common stock (in shares)			493,791
Exercise of stock options and vesting of restricted stock for common stock (in shares)	75,419	68,069	149,886
Acquisition of treasury stock (in shares)	76,300	65,171