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Columns in Cash Flows statement 'Consolidated Statements of Cash Flows (USD $)' have maximum duration 365 days and at least 37 values. Shorter duration columns must have at least one fourth (9) as many values. Column '10/1/2013 - 12/31/2013' is shorter (91 days) and has only 4 values, so it is being removed. Columns in Cash Flows statement 'Consolidated Statements of Cash Flows (USD $)' have maximum duration 365 days and at least 37 values. Shorter duration columns must have at least one fourth (9) as many values. Column '1/1/2014 - 3/31/2014' is shorter (89 days) and has only 2 values, so it is being removed. Columns in Cash Flows statement 'Consolidated Statements of Cash Flows (USD $)' have maximum duration 365 days and at least 37 values. Shorter duration columns must have at least one fourth (9) as many values. Column '4/1/2014 - 6/30/2014' is shorter (90 days) and has only 1 values, so it is being removed. Columns in Cash Flows statement 'Consolidated Statements of Cash Flows (USD $)' have maximum duration 365 days and at least 37 values. Shorter duration columns must have at least one fourth (9) as many values. Column '7/1/2014 - 9/30/2014' is shorter (91 days) and has only 1 values, so it is being removed. Columns in Cash Flows statement 'Consolidated Statements of Cash Flows (USD $)' have maximum duration 365 days and at least 37 values. Shorter duration columns must have at least one fourth (9) as many values. Column '10/1/2014 - 12/31/2014' is shorter (91 days) and has only 2 values, so it is being removed. 'Monetary' elements on report '1045 - Disclosure - Organization and Summary of Significant Accounting Policies - Additional Information (Detail)' had a mix of different decimal attribute values. 'Monetary' elements on report '1051 - Disclosure - Investments - Additional Information (Detail)' had a mix of different decimal attribute values. 'Monetary' elements on report '1067 - Disclosure - Ceded Reinsurance - Additional Information (Detail)' had a mix of different decimal attribute values. 'Monetary' elements on report '1072 - Disclosure - Income Taxes - Additional Information (Detail)' had a mix of different decimal attribute values. 'Monetary' elements on report '1077 - Disclosure - Senior Notes - Additional Information (Detail)' had a mix of different decimal attribute values. 'Shares' elements on report '1082 - Disclosure - Changes in Issued and Outstanding Common Shares (Detail)' had a mix of different decimal attribute values. 'Monetary' elements on report '1085 - Disclosure - Dividends and Statutory Financial Information - Additional Information (Detail)' had a mix of different decimal attribute values. 'Monetary' elements on report '1086 - Disclosure - Stock Option Plans, Stock Grants, Stock Appreciation Rights and Employee Stock Purchase Plan - Additional Information (Detail)' had a mix of different decimal attribute values. Columns in Cash Flows statement 'Condensed Financial Information - Statement of Cash Flows (Detail) (USD $)' have maximum duration 365 days and at least 40 values. Shorter duration columns must have at least one fourth (10) as many values. Column '1/1/2013 - 3/31/2013' is shorter (89 days) and has only 3 values, so it is being removed. Columns in Cash Flows statement 'Condensed Financial Information - Statement of Cash Flows (Detail) (USD $)' have maximum duration 365 days and at least 40 values. Shorter duration columns must have at least one fourth (10) as many values. Column '4/1/2013 - 6/30/2013' is shorter (90 days) and has only 1 values, so it is being removed. Columns in Cash Flows statement 'Condensed Financial Information - Statement of Cash Flows (Detail) (USD $)' have maximum duration 365 days and at least 40 values. Shorter duration columns must have at least one fourth (10) as many values. Column '7/1/2013 - 9/30/2013' is shorter (91 days) and has only 1 values, so it is being removed. Columns in Cash Flows statement 'Condensed Financial Information - Statement of Cash Flows (Detail) (USD $)' have maximum duration 365 days and at least 40 values. Shorter duration columns must have at least one fourth (10) as many values. Column '10/1/2013 - 12/31/2013' is shorter (91 days) and has only 4 values, so it is being removed. Columns in Cash Flows statement 'Condensed Financial Information - Statement of Cash Flows (Detail) (USD $)' have maximum duration 365 days and at least 40 values. Shorter duration columns must have at least one fourth (10) as many values. Column '1/1/2014 - 3/31/2014' is shorter (89 days) and has only 3 values, so it is being removed. Columns in Cash Flows statement 'Condensed Financial Information - Statement of Cash Flows (Detail) (USD $)' have maximum duration 365 days and at least 40 values. Shorter duration columns must have at least one fourth (10) as many values. Column '4/1/2014 - 6/30/2014' is shorter (90 days) and has only 1 values, so it is being removed. Columns in Cash Flows statement 'Condensed Financial Information - Statement of Cash Flows (Detail) (USD $)' have maximum duration 365 days and at least 40 values. Shorter duration columns must have at least one fourth (10) as many values. Column '7/1/2014 - 9/30/2014' is shorter (91 days) and has only 1 values, so it is being removed. Columns in Cash Flows statement 'Condensed Financial Information - Statement of Cash Flows (Detail) (USD $)' have maximum duration 365 days and at least 40 values. Shorter duration columns must have at least one fourth (10) as many values. Column '10/1/2014 - 12/31/2014' is shorter (91 days) and has only 3 values, so it is being removed. Process Flow-Through: 1003 - Statement - Consolidated Balance Sheets Process Flow-Through: Removing column 'Dec. 31, 2012' Process Flow-Through: Removing column 'Dec. 31, 2011' Process Flow-Through: 1004 - Statement - Consolidated Balance Sheets (Parenthetical) Process Flow-Through: 1005 - Statement - Consolidated Statements of Income Process Flow-Through: 1006 - Statement - Consolidated Statements of Comprehensive Income Process Flow-Through: Removing column '3 Months Ended Dec. 31, 2014' Process Flow-Through: Removing column '3 Months Ended Sep. 30, 2014' Process Flow-Through: Removing column '3 Months Ended Jun. 30, 2014' Process Flow-Through: Removing column '3 Months Ended Mar. 31, 2014' Process Flow-Through: Removing column '3 Months Ended Dec. 31, 2013' Process Flow-Through: Removing column '3 Months Ended Sep. 30, 2013' Process Flow-Through: Removing column '3 Months Ended Jun. 30, 2013' Process Flow-Through: Removing column '3 Months Ended Mar. 31, 2013' Process Flow-Through: 1007 - Statement - Consolidated Statements of Comprehensive Income (Parenthetical) Process Flow-Through: 1009 - Statement - Consolidated Statements of Cash Flows Process Flow-Through: 1010 - Statement - Consolidated Statements of Cash Flows (Parenthetical) navg-20141231.xml navg-20141231.xsd navg-20141231_cal.xml navg-20141231_def.xml navg-20141231_lab.xml navg-20141231_pre.xml true true