Income Taxes (Significant Components of Deferred Tax Assets and Liabilities) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Deferred Tax Assets, Operating Loss Carryforwards, Domestic	$ 4,197	$ 4,819
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount	38,279	185,548	$ 175,445
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount	(744)	2,286	(5,390)
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount	74	1	1
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions	2,184	8,717	7,395
Foreign Income Tax Expense (Benefit), Continuing Operations	5,668	0	0
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Amount	(1,445)	0	0
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount	1,695	791	1,577
Income Tax Expense (Benefit)	45,711	197,343	$ 179,028
Deferred Tax Assets, Tax Credit Carryforwards, Research	1,833	1,990
Deferred Tax Liabilities, Intangible Assets	494	0
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost	835	465
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Reserves	1,966	1,146
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Provision for Loan Losses	0	5,526
Deferred Tax Assets, Capital Loss Carryforwards	1,543	2,286
Deferred Tax Assets, Other	13,020	12,023
Deferred Tax Assets, Gross	23,888	28,255
Deferred Tax Assets, Valuation Allowance	(1,543)	(2,286)
Deferred Tax Assets, Net of Valuation Allowance	22,345	25,969
Deferred Tax Liabilities, Tax Deferred Income	382	572
Deferred Tax Liabilities, Financing Arrangements	122	0
Deferred Tax Liabilities, Intangible Assets	(2,584)	(7,029)
Deferred Tax Liabilities, Unrealized Currency Transaction Gains	0	(1,215)
Deferred Tax Liabilities, Gross	(3,088)	(8,816)
Deferred Tax Assets, Net	$ 19,257	$ 17,153