Reconciliation of Total Segment Assets to Total Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting [Abstract]
Total segment assets	$ 3,144,625	$ 3,209,679	$ 3,225,617
Other assets	48,054	64,457
Total assets	$ 3,192,679	$ 3,274,136