Goodwill and Other Intangible Assets (Details 1) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Finite-Lived Intangible Assets, Future Amortization Expense [Abstract]
Remainder of 2012			$ 10,748,000
2013			19,710,000
2014			17,298,000
2015			15,429,000
2016			12,201,000
Thereafter			32,541,000
Total			107,927,000
Other Intangible Assets
Gross Carrying Amount	152,932,000		152,932,000		129,075,000
Accumulated Amortization	(45,005,000)		(45,005,000)		(36,672,000)
Net Carrying Amount	107,927,000		107,927,000		92,403,000
Aggregate amortization expense	5,342,000	2,604,000	10,218,000	5,259,000
Goodwill and Other Intangible Assets (Textuals) [Abstract]
Accumulated impairment losses	21,300,000		21,300,000
Noncontractual customer relationships [Member]
Other Intangible Assets
Gross Carrying Amount	101,683,000		101,683,000		82,891,000
Accumulated Amortization	(28,103,000)		(28,103,000)		(21,147,000)
Net Carrying Amount	73,580,000		73,580,000		61,744,000
Covenants not-to-compete [Member]
Other Intangible Assets
Gross Carrying Amount	12,859,000		12,859,000		13,035,000
Accumulated Amortization	(7,020,000)		(7,020,000)		(8,067,000)
Net Carrying Amount	5,839,000		5,839,000		4,968,000
Favorable lease asset [Member]
Other Intangible Assets
Gross Carrying Amount	7,163,000		7,163,000		5,571,000
Accumulated Amortization	(3,568,000)		(3,568,000)		(3,210,000)
Net Carrying Amount	3,595,000		3,595,000		2,361,000
Trademarks [Member]
Other Intangible Assets
Gross Carrying Amount	7,898,000		7,898,000		7,405,000
Accumulated Amortization	(1,995,000)		(1,995,000)		(1,686,000)
Net Carrying Amount	5,903,000		5,903,000		5,719,000
Contracts [Member]
Other Intangible Assets
Gross Carrying Amount	4,062,000		4,062,000		3,500,000
Accumulated Amortization	(437,000)		(437,000)		(185,000)
Net Carrying Amount	3,625,000		3,625,000		3,315,000
Technology [Member]
Other Intangible Assets
Gross Carrying Amount	19,183,000		19,183,000		16,589,000
Accumulated Amortization	(3,832,000)		(3,832,000)		(2,342,000)
Net Carrying Amount	15,351,000		15,351,000		14,247,000
Client lists [Member]
Other Intangible Assets
Gross Carrying Amount	84,000		84,000		84,000
Accumulated Amortization	(50,000)		(50,000)		(35,000)
Net Carrying Amount	$ 34,000		$ 34,000		$ 49,000