Summary of Significant Accounting Policies (Cash and Cash Equivalents) - Additional Information (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2014
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	$ 155,315	$ 128,771	$ 135,534	$ 190,515
Cash equivalents	7,400	1,400
Investments in Joint Ventures [Member]
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	28,300	24,900
Domestic Joint Ventures [Member]
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	17,000	11,900
Domestic Bank Accounts [Member]
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	18,300	16,100
Foreign Bank Accounts [Member]
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	$ 137,000	$ 112,700