Goodwill, Intangible Assets and Deferred Charge - Schedule of Goodwill, Intangible Assets and Deferred Charges (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Goodwill [Roll Forward]
Goodwill, Beginning balance	$ 73,071
Goodwill, Acquired during the year	0
Goodwill, Ending balance	73,071
Finite-lived Intangible Assets [Roll Forward]
Intangible assets with a definite life, Amortization	(100)	$ (2,700)
Indefinite-lived Intangible Assets [Roll Forward]
Intangible assets with an indefinite life, Beginning balance	87,031
Intangible assets with an indefinite life, Acquired during the year	0
Intangible assets with an indefinite life, Ending balance	87,031
Goodwill and Intangible Assets [Roll Forward]
Goodwill and intangible assets, Beginning Balance	191,304
Goodwill and intangible assets, Acquired during the year	0
Intangible assets with a definite life, Amortization	(100)	$ (2,700)
Goodwill and intangible assets, Ending balance	187,888
Deferred Charges [Roll Forward]
Other assets - Deferred Charge, Beginning balance	255,911
Other assets - Deferred Charge, Acquired during the year	0
Other assets - Deferred Charge, Amortization	(1,611)
Other assets - Deferred Charge, Ending balance	254,300
Fair Value Adjustments
Finite-lived Intangible Assets [Roll Forward]
Intangible assets with a definite life, Beginning balance	180,730
Intangible assets with a definite life, Acquired during the year	0
Intangible assets with a definite life, Amortization	3,277
Intangible assets with a definite life, Ending balance	184,007
Goodwill and Intangible Assets [Roll Forward]
Intangible assets with a definite life, Amortization	3,277
Other
Finite-lived Intangible Assets [Roll Forward]
Intangible assets with a definite life, Beginning balance	31,202
Intangible assets with a definite life, Acquired during the year	0
Intangible assets with a definite life, Amortization	(3,416)
Intangible assets with a definite life, Ending balance	27,786
Goodwill and Intangible Assets [Roll Forward]
Intangible assets with a definite life, Amortization	$ (3,416)