Commitments and Contingencies:

6 Months Ended

Jun. 30, 2018

Commitments and Contingencies:

Commitments and Contingencies:

12.  Commitments and Contingencies:

In May 2018, the Company entered into an amendment to its lease for its corporate headquarters facility that, among other things, provides for an extension of the lease term for ten years and four months, commencing on September 1, 2019.  The Company is obligated to pay rent monthly under the lease, and will pay an estimated $8.0 million in total rental payments over the entire term of the extended period of the lease.  The Company is also obligated to pay estimated taxes and operating expenses (which change annually).