Fair Value Measurements (Narrative) (Detail) (USD $)					9 Months Ended
	Sep. 30, 2014		Dec. 31, 2013		Sep. 30, 2014 Alternative investments [Member]	Sep. 30, 2014 Cost-method Investments [Member] Alternative investments [Member]	Sep. 30, 2014 Fair Value, Measurements, Recurring [Member] Alternative investments [Member]	Dec. 31, 2013 Fair Value, Measurements, Recurring [Member] Alternative investments [Member]	Sep. 30, 2014 Fair Value, Measurements, Recurring [Member] Cost-method Investments [Member] Rabbi Trust [Member]	Sep. 30, 2014 Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument, Unamortized Discount	$ 1,112,000	[1]	$ 21,000	[1]
Alternative investments (cost basis)						16,200,000	477,000	565,000	4,600,000
Unfunded commitment for investments					6,900,000
Book value of other real estate owned (OREO) and repossessed assets										$ 5,200,000

[1] Related to senior fixed-rate notes due 2024 at September 30, 2014 and senior fixed-rate notes due 2014 at December 31, 2013