Long-Term Borrowings - Unsecured Long-Term Borrowings after Hedging (Parenthetical) (Detail)	Sep. 30, 2016	Dec. 31, 2015
Debt Disclosure [Abstract]
Effective weighted average interest rates for unsecured long-term borrowings, after hedging - total	2.82%	2.73%
Effective weighted average interest rates for unsecured long-term borrowings, after hedging fixed rate obligations	4.06%	4.33%
Effective weighted average interest rates for unsecured long-term borrowings, after hedging - floating rate obligations	1.85%	1.84%