Pension Assets By Components At Fair Value (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011
Schedule of Pension and Other Postretirerment Plan Assets by Fair Value [Line Items]
Defined benefit pension plans-Fair value of plan assets	$ 277,641		$ 258,067
Total percentage	100.00%		100.00%
Equity Securities, Financial
Schedule of Pension and Other Postretirerment Plan Assets by Fair Value [Line Items]
Defined benefit pension plans-Fair value of plan assets	26,174		24,255
Total percentage	9.00%		9.00%
Equity Securities, Consumer, Non-Cyclical
Schedule of Pension and Other Postretirerment Plan Assets by Fair Value [Line Items]
Defined benefit pension plans-Fair value of plan assets	15,894		14,866
Total percentage	6.00%		6.00%
Equity Securities, Technology
Schedule of Pension and Other Postretirerment Plan Assets by Fair Value [Line Items]
Defined benefit pension plans-Fair value of plan assets	13,332		13,184
Total percentage	5.00%		5.00%
Equity Securities Industrial
Schedule of Pension and Other Postretirerment Plan Assets by Fair Value [Line Items]
Defined benefit pension plans-Fair value of plan assets	10,353		11,491
Total percentage	4.00%		5.00%
Equity Securities, General Merchandise Stores
Schedule of Pension and Other Postretirerment Plan Assets by Fair Value [Line Items]
Defined benefit pension plans-Fair value of plan assets	11,197		8,119
Total percentage	4.00%		3.00%
Equity Securities, Other
Schedule of Pension and Other Postretirerment Plan Assets by Fair Value [Line Items]
Defined benefit pension plans-Fair value of plan assets	12,883		7,544
Total percentage	4.00%		3.00%
Equity Securities
Schedule of Pension and Other Postretirerment Plan Assets by Fair Value [Line Items]
Defined benefit pension plans-Fair value of plan assets	89,833		79,459
Total percentage	32.00%		31.00%
Corporate Bonds
Schedule of Pension and Other Postretirerment Plan Assets by Fair Value [Line Items]
Defined benefit pension plans-Fair value of plan assets	169,817		159,759
Total percentage	61.00%		62.00%
Other Bonds
Schedule of Pension and Other Postretirerment Plan Assets by Fair Value [Line Items]
Defined benefit pension plans-Fair value of plan assets	327		348
Total percentage	0.00%		0.00%
Guaranteed Annuity Contract
Schedule of Pension and Other Postretirerment Plan Assets by Fair Value [Line Items]
Defined benefit pension plans-Fair value of plan assets	13,277	[1]	12,745	[1]
Total percentage	5.00%	[1]	5.00%	[1]
Short-term Investments
Schedule of Pension and Other Postretirerment Plan Assets by Fair Value [Line Items]
Defined benefit pension plans-Fair value of plan assets	2,218		3,767
Total percentage	1.00%		1.00%
Other
Schedule of Pension and Other Postretirerment Plan Assets by Fair Value [Line Items]
Defined benefit pension plans-Fair value of plan assets	2,169		1,989
Total percentage	1.00%		1.00%
Fair Value, Inputs, Level 1
Schedule of Pension and Other Postretirerment Plan Assets by Fair Value [Line Items]
Defined benefit pension plans-Fair value of plan assets	98,512		91,876
Fair Value, Inputs, Level 1 | Equity Securities, Financial
Schedule of Pension and Other Postretirerment Plan Assets by Fair Value [Line Items]
Defined benefit pension plans-Fair value of plan assets	26,174		24,255
Fair Value, Inputs, Level 1 | Equity Securities, Consumer, Non-Cyclical
Schedule of Pension and Other Postretirerment Plan Assets by Fair Value [Line Items]
Defined benefit pension plans-Fair value of plan assets	15,894		14,866
Fair Value, Inputs, Level 1 | Equity Securities, Technology
Schedule of Pension and Other Postretirerment Plan Assets by Fair Value [Line Items]
Defined benefit pension plans-Fair value of plan assets	13,332		13,184
Fair Value, Inputs, Level 1 | Equity Securities Industrial
Schedule of Pension and Other Postretirerment Plan Assets by Fair Value [Line Items]
Defined benefit pension plans-Fair value of plan assets	10,353		11,491
Fair Value, Inputs, Level 1 | Equity Securities, General Merchandise Stores
Schedule of Pension and Other Postretirerment Plan Assets by Fair Value [Line Items]
Defined benefit pension plans-Fair value of plan assets	11,197		8,119
Fair Value, Inputs, Level 1 | Equity Securities, Other
Schedule of Pension and Other Postretirerment Plan Assets by Fair Value [Line Items]
Defined benefit pension plans-Fair value of plan assets	12,883		7,544
Fair Value, Inputs, Level 1 | Equity Securities
Schedule of Pension and Other Postretirerment Plan Assets by Fair Value [Line Items]
Defined benefit pension plans-Fair value of plan assets	89,833		79,459
Fair Value, Inputs, Level 1 | Corporate Bonds
Schedule of Pension and Other Postretirerment Plan Assets by Fair Value [Line Items]
Defined benefit pension plans-Fair value of plan assets	4,292		6,661
Fair Value, Inputs, Level 1 | Short-term Investments
Schedule of Pension and Other Postretirerment Plan Assets by Fair Value [Line Items]
Defined benefit pension plans-Fair value of plan assets	2,218		3,767
Fair Value, Inputs, Level 1 | Other
Schedule of Pension and Other Postretirerment Plan Assets by Fair Value [Line Items]
Defined benefit pension plans-Fair value of plan assets	2,169		1,989
Fair Value, Inputs, Level 2
Schedule of Pension and Other Postretirerment Plan Assets by Fair Value [Line Items]
Defined benefit pension plans-Fair value of plan assets	179,129		166,191
Fair Value, Inputs, Level 2 | Corporate Bonds
Schedule of Pension and Other Postretirerment Plan Assets by Fair Value [Line Items]
Defined benefit pension plans-Fair value of plan assets	165,525		153,098
Fair Value, Inputs, Level 2 | Other Bonds
Schedule of Pension and Other Postretirerment Plan Assets by Fair Value [Line Items]
Defined benefit pension plans-Fair value of plan assets	327		348
Fair Value, Inputs, Level 2 | Guaranteed Annuity Contract
Schedule of Pension and Other Postretirerment Plan Assets by Fair Value [Line Items]
Defined benefit pension plans-Fair value of plan assets	13,277	[1]	12,745	[1]
Fair Value, Inputs, Level 3
Schedule of Pension and Other Postretirerment Plan Assets by Fair Value [Line Items]
Defined benefit pension plans-Fair value of plan assets	$ 0		$ 0

[1] Annuity contract issued by a Torchmark subsidiary