Stock-Based Compensation - Equity-Classified Stock Compensation (Market Condition Grants of Restricted Shares) - Additional Information (Detail)		3 Months Ended			12 Months Ended
	Jan. 31, 2015 shares	Jun. 30, 2015 Increment shares	Mar. 31, 2015 shares	Dec. 31, 2014 shares	Dec. 31, 2015 USD ($) Increment Indicator $ / shares shares	Dec. 31, 2014 shares	Dec. 31, 2012 shares	Dec. 31, 2011 shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted shares vesting description					The restricted shares will vest in six increments based upon the price per share of the Company’s common stock during the term of their employment (or within sixty days after termination of employment by the Company without cause), meeting or exceeding the target trailing sixty-day average closing prices ranging from $36 per share for the first increment to $65 per share for the final increment.
Restricted share award closing prices range per share, Minimum | $ / shares					$ 36
Restricted share award closing prices range per share, Maximum | $ / shares					$ 65
Restricted share award average closing prices, period					60 days
Number of increments had vested | Increment					6
Mr Albright [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of increments had vested | Increment		0			4
Mr Patten [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of increments had vested | Increment					4
Mr Smith [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted shares vesting description					The restricted stock will vest in two increments based upon the price per share of Company common stock during the term of their employment (or within sixty days after termination of employment by the Company without cause), meeting or exceeding the target trailing sixty-day average closing prices of $60 per share and $65 per share for the two increments.
Restricted share award closing prices range per share, Minimum | $ / shares					$ 60
Restricted share award closing prices range per share, Maximum | $ / shares					$ 65
Restricted share award average closing prices, period					60 days
Number of increments had vested | Increment					0
Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of increments had vested | Indicator					0
Restricted Shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation cost related to market condition non-vested restricted shares | $					$ 1,000
Weighted average period of compensation cost to be recognized					18 days
Restricted Shares [Member] | 2010 Plan [Member] | Mr Albright [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based compensation, Shares, Granted	8,000	94,000					96,000	96,000
Restricted Shares [Member] | 2010 Plan [Member] | Mr Patten [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based compensation, Shares, Granted							17,000	17,000
Restricted Shares [Member] | 2010 Plan [Member] | Mr Smith [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based compensation, Shares, Granted				2,500
Restricted Shares [Member] | 2010 Plan [Member] | Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based compensation, Shares, Granted			3,000
Inducement Grant of Restricted Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based compensation, Shares, Granted					97,000	2,500
Unrecognized compensation cost related to market condition non-vested restricted shares | $					$ 2,200,000
Weighted average period of compensation cost to be recognized					1 year 2 months 12 days