Commitments and Contingencies - Additional Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	0 Months Ended			12 Months Ended								3 Months Ended	12 Months Ended			0 Months Ended
	Oct. 31, 2011	Jul. 15, 2009	Jan. 02, 2009	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Buildings [Member]	Dec. 31, 2012 Buildings [Member]	Dec. 31, 2013 LFCM Holdings [Member]	Dec. 31, 2012 LFCM Holdings [Member]	Dec. 31, 2011 LFCM Holdings [Member]	Mar. 31, 2013 Class A Common Stock [Member]	Dec. 31, 2013 Class A Common Stock [Member]	Dec. 31, 2012 Class A Common Stock [Member]	Dec. 31, 2013 Class A Common Stock [Member] Maximum [Member]	Jul. 15, 2009 Initial Shares [Member]	Jul. 15, 2009 Earnout Shares [Member]
Contingencies And Commitments [Line Items]
Office space under agreement, expires through				2033
Rental expense relating to operating leases				$ 86,504	$ 80,888	$ 76,718
Sublease income				11,404	9,613	10,967			4,136	3,290	2,192
Capital lease obligation payable through				2017
Weighted average interest rate of capital				6.20%
Obligations collateralized by certain assets with a net book value							19,876	21,932
Book value of assets under capital lease				20,806	23,486
Liabilities of abandoned leased facilities in the U.K.				11,203	7,516
Guarantees indemnifications				5,897
Collateral/counter-guarantees				4,993
Payment for equity interests in LAM	90,000		60,000
Issue of Class A common stock	2,210,520
Withheld shares for tax obligations in lieu of delivery of shares	68,384
Additional cash payment subject to delayed payment/issuance until eighth anniversary				961	961
Additional issuance of Class A common shares subject to delayed payment/issuance until eighth anniversary				24,537	24,537
Aggregate fair value of consideration recognized by the company at acquisition date		61,624
Additional shares issued and subject to earnout criteria and payable over time																1,142,857	1,142,857
Earnout shares earned				1,371,992	1,209,154
Earnout shares became settled				1,029,006	686,004
Common stock issuable on contingent basis				0									107,617		202,650
Common stock issuable on non-contingent basis														170,988
Common stock issued on non-contingent basis												170,988
Maximum obligation to pay earn-out consideration if certain performance thresholds are achieved				$ 7,000	$ 7,000