Quarterly Results of Operations (Unaudited) - Additional Information (Detail) $ in Thousands	3 Months Ended			12 Months Ended
	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($) Acquisition	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Interim Reporting [Line Items]
Merger and acquisition related costs before tax		$ 1,500	$ 8,400	$ 11,682	$ 9,248
Merger and acquisition related costs after tax		$ 3,200	7,300
Debt issuance Cost Write Off Before Tax			3,000
Debt issuance Cost Write Off After Tax			$ 1,900
Number Of business acquisitions closed | Acquisition			4
PEP [Member]
Interim Reporting [Line Items]
Merger and acquisition related costs before tax	$ 18,700
Merger and acquisition related costs after tax	11,600
Debt issuance Cost Write Off Before Tax	18,700
Debt issuance Cost Write Off After Tax	$ 12,000