Subsequent Event (Details) $ / shares in Units, $ in Thousands			1 Months Ended	3 Months Ended	9 Months Ended
	Nov. 03, 2015 USD ($) territory property	Oct. 01, 2015 USD ($)	Oct. 31, 2015 $ / shares	Sep. 30, 2015 $ / shares	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)
Subsequent Event [Line Items]
Dividends per share amount | $ / shares				$ 0.13
Cash consideration, net of cash acquired | $					$ 112,090	$ 49,231
Subsequent Event [Member]
Subsequent Event [Line Items]
Redeemed aggregate principal amount of notes | $		$ 175,000
Dividends, declared date			Oct. 26, 2015
Dividends per share amount | $ / shares			$ 0.145
Increase in regular quarterly cash dividend per share | $ / shares			$ 0.015
Dividends, date to be paid			Nov. 23, 2015
Dividends, date of record			Nov. 09, 2015
Subsequent Event [Member] | Rock River Environmental Services Inc [Member]
Subsequent Event [Line Items]
Number of counties that operations were acquired in | territory	19
Number of collection operations acquired	5
Number of landfills acquired	2
Number of compost facilities acquired	1
Number of transfer stations acquired	1
Number of recycling facilities acquired	1
Cash consideration, net of cash acquired | $	$ 225,000