Subsequent Event - Additional Information (Detail) (USD $)	3 Months Ended							0 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Apr. 17, 2014 Subsequent Event [Member]	Jun. 30, 2014 Scenario, Forecast [Member]	Mar. 31, 2014 Series B [Member]	Mar. 31, 2014 Term Loan [Member]	Jan. 15, 2014 Wright Insurance Group, LLC [Member]
Subsequent Event [Line Items]
Aggregate purchase price of acquisitions	$ 1,324,000		$ 1,071,000					$ 602,500,000
Additional consideration in cash								37,500,000
Unsecured revolving credit facility				800,000,000
Unsecured term loans				550,000,000
Aggregate amount				1,850,000,000
Line of credit facility termination period	Apr. 16, 2019
Line of credit facility repayment period	5 years
Reserve amount to pay off outstanding long term debt	480,000,000	480,000,000					230,000,000
Reserve amount to pay off notes						$ 100,000,000
Line of credit facility interest rate above adjusted libor rate	1.375%				1.375%