Condensed Financial Information of Registrant (Parent Only) Balance Sheets (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011	Dec. 31, 2010
ASSETS
Cash and cash equivalents	$ 105,492		$ 104,460		$ 175,860	$ 119,888
Other assets	22,812		17,684
Total assets	1,911,779		1,903,703		2,072,916
Liabilities:
Other liabilities	22,955		22,182
Total liabilities	1,038,499		1,097,085
Commitments and contingencies
Shareholders' equity:
Ordinary shares, $0.0001 par value, 900,000,000 ordinary shares authorized; A ordinary shares issued: 16,200,406 and 16,087,939, respectively; A ordinary shares outstanding: 13,141,035 and 13,030,938, respectively; B ordinary shares issued and outstanding: 12,061,370 and 12,061,370, respectively	3		3
Additional paid-in capital	516,653		512,304
Accumulated other comprehensive income, net of tax	54,028		53,350
Retained earnings	403,861		342,171		307,413
A ordinary shares in treasury, at cost: 3,059,371 and 3,057,001 shares, respectively	(101,265)		(101,210)
Total shareholders' equity	873,280		806,618		839,063
Total liabilities and shareholders' equity	1,911,779		1,903,703		2,072,916
Parent Company
ASSETS
Cash and cash equivalents	1,746		1,744		9,792	51
Equity in unconsolidated subsidiaries	982,396	[1]	933,989	[1]
Other assets	683		1,004
Total assets	984,825		936,737
Liabilities:
Intercompany notes payable	108,000	[1]	108,000	[1]
Due to affiliates	139	[1]	19,554	[1]
Other liabilities	3,351		2,510
Total liabilities	111,490		130,064
Commitments and contingencies
Shareholders' equity:
Ordinary shares, $0.0001 par value, 900,000,000 ordinary shares authorized; A ordinary shares issued: 16,200,406 and 16,087,939, respectively; A ordinary shares outstanding: 13,141,035 and 13,030,938, respectively; B ordinary shares issued and outstanding: 12,061,370 and 12,061,370, respectively	3		3
Deferred shares, €1 par value, 40,000 ordinary shares authorized, issued and outstanding	55	[1]	55	[1]
Preferred shares, $0.0001 par value, 100,000,000 shares authorized, none issued and outstanding
Additional paid-in capital	516,653		512,304
Accumulated other comprehensive income, net of tax	54,028		53,350
Retained earnings	403,861		342,171
A ordinary shares in treasury, at cost: 3,059,371 and 3,057,001 shares, respectively	(101,265)		(101,210)
Total shareholders' equity	873,335		806,673
Total liabilities and shareholders' equity	$ 984,825		$ 936,737

[1] This item has been eliminated in the Company's Consolidated Financial Statements.