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-Name Accounting Standards Codification
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Segment Information - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Revenues	$ 319,950	$ 245,525	$ 234,995	$ 209,310	$ 326,395	$ 225,735	$ 240,599	$ 231,462	$ 1,009,780	$ 1,024,191	$ 1,005,701
Operating income	$ 116,414	$ 28,359	$ (2,158)	$ (16,704)	$ 108,037	$ 11,423	$ (38,443)	$ 3,623	$ 125,911	84,640	221,130
BHMI judgment and related fees										48,100
General and Administrative Expense [Member]
Segment Reporting Information [Line Items]
BHMI judgment and related fees										$ 46,700
Community Financial Services Products [Member] \| Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Revenues											15,400
Operating income											$ 151,700
Customer Concentration Risk [Member]
Segment Reporting Information [Line Items]
Description of customer revenue accounted for more than 10% of consolidated revenue									No single customer accounted for more than 10% of the Company’s consolidated revenues during the years ended December 31, 2018, 2017, and 2016.
Geographic Concentration Risk [Member]
Segment Reporting Information [Line Items]
Description of customer revenue accounted for more than 10% of consolidated revenue									No other country outside the United States accounted for more than 10% of the Company’s consolidated revenues during the years ended December 31, 2018, 2017, and 2016.