Commitments and Contingencies (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) property	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Commitment and contingencies [Line Items]
Deferred Rent Credit, Current	$ 500	$ 300
Operating Leases
2016	18,369
2017	15,533
2018	12,994
2019	9,989
2020	7,573
Thereafter	11,854
Total	76,312
Related Party
2016	1,190
2017	1,169
2018	1,302
2019	1,282
2020	1,314
Thereafter	5,346
Total	11,603
Total
2016	19,559
2017	16,702
2018	14,296
2019	11,271
2020	8,887
Thereafter	17,200
Total	87,915
Deferred rent liability, noncurrent	4,300	4,000
Rent expense	21,600	17,600	$ 15,400
Costs and Expenses, Related Party	1,300	1,300	$ 1,300
Self Insurance Reserve	1,800	2,200
Workerscompensationreceivable	13,238	13,370
Letters of credit outstanding	$ 3,500	$ 3,200
Apex Systems
Total
Number of leased properties owned by related parties (in number of properties) | property	2