Leases - Additional Information (Detail) - USD ($) $ in Millions |
3 Months Ended | |
---|---|---|
Mar. 31, 2019 |
Mar. 31, 2018 |
|
Lessee Lease Description [Line Items] | ||
Operating lease, existence of option to extend | true | |
Operating lease, options to extend | Some of these leases have options to extend which, if exercised, would extend the maximum term to approximately 24 years. | |
Operating lease, existence of option to terminate | true | |
Operating lease, options to terminate | Some of the leases also provide for early termination, the exercise of which would shorten the term of those leases by up to 5 years. | |
Operating lease, expense | $ 7.3 | |
Rent expense for office space | $ 6.3 | |
Maximum [Member] | ||
Lessee Lease Description [Line Items] | ||
Operating lease, remaining lease terms | 14 years | |
Operating lease, extended term | 24 years | |
Operating lease, early termination term | 8 years |