Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions	Apr. 30, 2016	Mar. 31, 2016	Dec. 31, 2015
Commitments and Contingencies
Line of credit, performance and payment bonds		$ 183.1	$ 183.0
Operating Partnership
Commitments and Contingencies
Outstanding letters of credit		$ 8.0	$ 8.0
Operating Partnership | Subsequent Event
Commitments and Contingencies
Outstanding letters of credit	$ 2.0