Stock-Based Compensation - Market Condition Restricted Shares, Stock Price Vesting (Details)		1 Months Ended		3 Months Ended				12 Months Ended					15 Months Ended
	Feb. 26, 2016 shares	May 31, 2015 $ / shares shares	Jan. 31, 2015 $ / shares shares	Mar. 31, 2016 USD ($) $ / shares shares	Jun. 30, 2015 shares	Mar. 31, 2015 $ / shares shares	Dec. 31, 2014 $ / shares shares	Dec. 31, 2016 USD ($) item $ / shares shares	Dec. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2014 $ / shares shares	Dec. 31, 2012 shares	Dec. 31, 2011 shares	Mar. 31, 2016 USD ($) $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
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
Mr Smith [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
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
2010 Plan [Member] | Mr Albright [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted shares vesting description		The New Restricted Share Grant is intended to have the same vesting terms as the May 2015 Restricted Share Grant, and as a result will vest upon the price per share of Company common stock during the term of Mr. Albright's employment (or within 60 days after termination of his employment by the Company other than for cause, due to death or disability or due to his voluntary resignation) meeting or exceeding the target trailing 30-day average closing price of $75 per share. If the restricted shares fail to satisfy the stock price condition prior to January 28, 2021, the restricted shares will be forfeited. Any unvested restricted shares will vest immediately upon Mr. Albright's termination of employment without Cause or for his resignation for Good Reason (as such terms are defined in his amended and restated employment agreement), in each case, at any time during the 24-month period following a change in control.
Restricted share award closing prices range per share, Minimum | $ / shares		$ 75
Restricted Shares [Member] | 2010 Plan [Member] | Mr Albright [Member]
Share-based Compensation, Other Than Options, Shares
Stock based compensation, Shares, Granted	4,000	94,000	8,000
Market Condition Restricted Shares - Stock Price Vesting | Restricted Shares [Member] | 2010 Plan [Member]
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.
Number of increments to vest | item								6
Share-based Compensation, Other Than Options, Shares
Stock based compensation, Shares Outstanding, beginning balance			40,500	137,500		40,500		137,500	40,500	94,500			40,500
Stock based compensation, Shares, Granted								4,000	97,000	2,500
Stock based compensation, Shares, Exercised										(56,500)
Stock based compensation, Shares, Forfeited								(72,000)
Stock based compensation, Shares Outstanding, ending balance							40,500	69,500	137,500	40,500
Share-based Compensation, Other Than Options, Weighted Average Fair Value
Stock based compensation, Weighted Average Fair Value Per Share, beginning balance | $ / shares			$ 15.55	$ 30.58		$ 15.55		$ 30.58	$ 15.55	$ 17.33			$ 15.55
Stock based compensation, Weighted Average Fair Value Per Share, Granted | $ / shares								38.98	36.85	38.97
Stock based compensation, Weighted Average Fair Value Per Share, Exercised | $ / shares										19.56
Stock based compensation, Weighted Average Fair Value Per Share, Forfeited | $ / shares								34.46
Stock based compensation, Weighted Average Fair Value Per Share, ending balance | $ / shares							$ 15.55	$ 27.03	$ 30.58	$ 15.55
Unrecognized compensation cost related to market condition non-vested restricted shares | $								$ 6,000
Weighted average period of compensation cost to be recognized								1 month 6 days
Market Condition Restricted Shares - Stock Price Vesting | Restricted Shares [Member] | 2010 Plan [Member] | Mr Albright [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted shares vesting description								The 26,000 shares of restricted Company common stock outstanding from these grants will vest in four increments based upon the price per share of Company common stock during the term of his employment (or within sixty days after termination of employment by the Company without cause), meeting or exceeding the target trailing thirty-day average closing prices ranging from $60 per share for the first increment to $75 per share for the final increment. If any increment of the restricted shares fails to satisfy the applicable stock price condition prior to January 28, 2021, that increment of the restricted shares will be forfeited.
Restricted share award closing prices range per share, Minimum | $ / shares								$ 60
Restricted share award closing prices range per share, Maximum | $ / shares								$ 75
Restricted share award average closing prices, period								30 days
Number of increments to vest | item								4
Stock based compensation, shares, surrendered	72,000
Stock based compensation, shares, permanently surrendered	68,000			68,000
Stock-based compensation expense | $				$ 1,600,000				$ 1,600,000	$ 676,000				$ 2,300,000
Share-based Compensation, Other Than Options, Shares
Stock based compensation, Shares, Granted	4,000				94,000						96,000	96,000
Stock based compensation, Shares Outstanding, ending balance								26,000
Market Condition Restricted Shares - Stock Price Vesting | Restricted Shares [Member] | 2010 Plan [Member] | Mr Patten [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of increments to vest | item								4
Share-based Compensation, Other Than Options, Shares
Stock based compensation, Shares, Granted											17,000	17,000
Market Condition Restricted Shares - Stock Price Vesting | Restricted Shares [Member] | 2010 Plan [Member] | 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.
Number of increments to vest | item								0
Share-based Compensation, Other Than Options, Shares
Stock based compensation, Shares, Granted							2,500
Market Condition Restricted Shares - Stock Price Vesting | Restricted Shares [Member] | 2010 Plan [Member] | Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of increments to vest | item								0
Share-based Compensation, Other Than Options, Shares
Stock based compensation, Shares, Granted						3,000