Commitments and Contingencies - Additional Information (Detail) - USD ($)	3 Months Ended
	Dec. 31, 2016	Mar. 31, 2017
Other Commitments [Line Items]
Guarantees indemnifications		$ 3,174,000
Collateral/counter-guarantees		3,092,000
LFB [Member]
Other Commitments [Line Items]
Other commitments		0
LFNY [Member]
Other Commitments [Line Items]
Other commitments		$ 0
Business Acquisitions [Member]
Other Commitments [Line Items]
Number of contingent additional shares earned		0
Business Acquisitions [Member] | Class A Common Stock [Member]
Other Commitments [Line Items]
Common stock issued and issuable	60,817
Business Acquisitions [Member] | Class A Common Stock [Member] | Non-Contingent [Member]
Other Commitments [Line Items]
Common stock issued and issuable	204,651
Business Acquisitions [Member] | Class A Common Stock [Member] | Maximum [Member]
Other Commitments [Line Items]
Contingent shares issuable upon satisfaction of performance thresholds	810,742