Fair Value Measurements - Summary of Activity for Assets Measured at Fair Value Using Significant Unobservable Inputs (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($)
Fair Value Disclosures [Abstract]
Balance at December 31, 2014	$ 1,971
Total net realized gains included in earnings	0
Total net unrealized gains included in other comprehensive income	81
Net transfers in and/out of Level 3	0
Balance at December 31, 2015	2,052
Amount of total losses for the period included in net loss attributable to the change in unrealized gains or losses relating to assets still held at December 31, 2015	$ 0