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Shareholders' Equity - Summary of Nonvested Share Activity (Detail) - shares | 12 Months Ended
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Dec. 31, 2018 | Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Awards vested, Number of Shares | (6,011,271) |
Employees [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Beginning Balance, Number of Shares | 13,155,039 |
Awards granted, Number of Shares | 8,018,493 |
Awards forfeited/waived, Number of Shares | (115,566) |
Awards cancelled on failed vesting conditions, Number of Shares | 0 |
Awards vested, Number of Shares | (6,011,271) |
Ending Balance, Number of Shares | 15,046,695 | 13,155,039
Employees [Member] | 2015 CEO Special Bonus [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Beginning Balance, Number of Shares | 17,789 |
Awards cancelled on failed vesting conditions, Number of Shares | 0 |
Awards vested, Number of Shares | (17,789) |
Ending Balance, Number of Shares |  | 17,789
Employees [Member] | Employee Plan 2015 [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Beginning Balance, Number of Shares | 1,630,784 |
Awards forfeited/waived, Number of Shares | (5,200) |
Awards cancelled on failed vesting conditions, Number of Shares | 0 |
Awards vested, Number of Shares | (1,625,584) |
Ending Balance, Number of Shares |  | 1,630,784
Employees [Member] | 2016 CEO Special Bonus [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Beginning Balance, Number of Shares | 46,110 |
Awards cancelled on failed vesting conditions, Number of Shares | 0 |
Awards vested, Number of Shares | (46,110) |
Ending Balance, Number of Shares |  | 46,110
Employees [Member] | Employee Plan 2016 [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Beginning Balance, Number of Shares | 3,512,846 |
Awards forfeited/waived, Number of Shares | (27,339) |
Awards cancelled on failed vesting conditions, Number of Shares | 0 |
Awards vested, Number of Shares | (1,681,367) |
Ending Balance, Number of Shares | 1,804,140 | 3,512,846
Employees [Member] | Employee Plan 2017 [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Beginning Balance, Number of Shares | 7,947,510 |
Awards forfeited/waived, Number of Shares | (61,997) |
Awards cancelled on failed vesting conditions, Number of Shares | 0 |
Awards vested, Number of Shares | (2,616,538) |
Ending Balance, Number of Shares | 5,268,975 | 7,947,510
Employees [Member] | 2017 CEO Special Bonus [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Awards granted, Number of Shares | 22,883 |
Awards cancelled on failed vesting conditions, Number of Shares | 0 |
Awards vested, Number of Shares | (22,883) |
Employees [Member] | Employee Plan 2018 [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Awards granted, Number of Shares | 7,995,610 |
Awards forfeited/waived, Number of Shares | (21,030) |
Awards cancelled on failed vesting conditions, Number of Shares | 0 |
Awards vested, Number of Shares | (1,000) |
Ending Balance, Number of Shares | 7,973,580 |
Supervisory Board [Member] | 2007 [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Beginning Balance, Number of Shares |  | 7,500
Year of grant | 2007 |
Exercised |  | (7,500)
Supervisory Board [Member] | 2008 [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Beginning Balance, Number of Shares | 16,500 | 24,000
Year of grant | 2008 |
Exercised | (16,500) | (7,500)
Ending Balance, Number of Shares |  | 16,500
Supervisory Board [Member] | 2009 [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Beginning Balance, Number of Shares | 22,500 | 35,000
Year of grant | 2009 |
Exercised | (22,500) | (12,500)
Ending Balance, Number of Shares |  | 22,500
Supervisory Board [Member] | 2010 [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Beginning Balance, Number of Shares | 30,000 | 45,000
Year of grant | 2010 |
Exercised | (7,500) | (15,000)
Ending Balance, Number of Shares | 22,500 | 30,000
Supervisory Board [Member] | 2011 [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Beginning Balance, Number of Shares | 52,500 | 67,500
Year of grant | 2011 |
Exercised |  | (15,000)
Ending Balance, Number of Shares | 52,500 | 52,500
Supervisory Board [Member] | 2012 [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Beginning Balance, Number of Shares | 65,000 | 87,500
Year of grant | 2012 |
Exercised |  | (22,500)
Ending Balance, Number of Shares | 65,000 | 65,000

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- Definition Share based compensation arrangement by share based payment award equity instruments other than options cancelled on failed vesting conditions in period. + References No definition available. + Details
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- Definition The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(iv)(3) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(i)-(ii) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(2) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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