Derivatives - Additional Information (Detail) $ in Thousands	Jun. 30, 2017 USD ($) derivative
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Estimated amount of unrealized gains or losses expected to be reclassified as interest expense in next fiscal year	$ 3,310
Number of derivative financial instruments | derivative	32
Combined notional amount	$ 2,341,756
Credit risk derivative, fair value of derivatives in a net liability position	1,846
Estimated termination value on settlement	$ 2,272