Leases - (Detail) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Jun. 30, 2018 USD ($) ft²	Jun. 30, 2018 USD ($) ft²	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($) ft²	Jun. 30, 2017 USD ($)	Apr. 20, 2018 ft²	Dec. 31, 2017
Lease terms
Option to extend				P20Y
Weighted-average remaining lease term	10 years	10 years		10 years			5 years
Weighted-average discount rate	4.90%	4.90%		4.90%			4.80%
Increase in Right-of-Use Asset				$ 96,790	$ 8,330
Lease expense
Operating lease expense		$ 5,418	$ 5,089	10,645	10,178
Variable lease expense		1,129	842	2,302	1,715
Rent expense		$ 6,547	$ 5,931	$ 12,947	$ 11,893
Weighted-average remaining lease term	10 years	10 years		10 years			5 years
Minimum
Lease terms
Remaining lease terms	1 year	1 year		1 year
Maximum
Lease terms
Remaining lease terms	11 years	11 years		11 years
LA1
Lease terms
Increase in Right-of-Use Asset	$ 91,400
Net rentable space | ft²	160,000	160,000		160,000
Area of Real Estate Property | ft²	17,238	17,238		17,238
US Colo Los Angeles California
Lease terms
Increase in Right-of-Use Asset	$ 5,300
Net rentable space | ft²						6,723