Investments in debt and equity securities available-for-sale - Gross Unrealized Gains and Losses (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Gains	$ 33,442	$ 18,179
Losses	836	3,714
Municipal
Schedule of Available-for-sale Securities [Line Items]
Gains	3,239	1,720
Losses	0	12
Corporate
Schedule of Available-for-sale Securities [Line Items]
Gains	16,994	7,700
Losses	10	2,109
Foreign
Schedule of Available-for-sale Securities [Line Items]
Gains	6,032	3,789
Losses	42	482
U.S. Treasury Bonds
Schedule of Available-for-sale Securities [Line Items]
Gains	153	128
Losses	0	25
Equity securities
Schedule of Available-for-sale Securities [Line Items]
Gains	7,024	4,842
Losses	$ 784	$ 1,086

Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27161-111563

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- Definition

Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27161-111563

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+ References

No definition available.

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