Share-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2015

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Transactions involving stock options under the terms of the LTSIP

Stock option transactions and balances under the terms of the LTSIP are summarized below:

	Options Outstanding		Exercise Price Range					Weighted-Average Exercise Price
Balance at December 31, 2014	435,507		$	11.40	-	$	17.35	$	12.46
Exercised	(178,112	)	11.40		-	13.10		11.47
Balance at December 31, 2015	257,395		$	11.40	-	$	17.35	$	13.14

Options held under the LTSIP, by exercise price range

Options Outstanding								Options Exercisable
Range of exercise prices				Number outstanding at Dec. 31, 2015	Weighted-average remaining term in years	Weighted-average exercise price		Number exercisable at Dec. 31, 2015	Weighted-average exercise price
$	11.40	$	17.35	257,395	0.8	$	13.14	257,395	$	13.14

Transactions involving restricted shares and RSUs under the terms of the LTSIP

Transactions involving RSUs under the terms of the LTSIP for the year ended December 31, 2015, are summarized below:

	RSUs Outstanding		Price Range					Weighted-Average Price
Balance at December 31, 2014	526,102		$	22.14	-	$	24.70	$	23.60
Granted	351,282		23.70		-	25.07		24.38
Vested	(294,515	)	22.14		-	25.07		23.68
Forfeited	(32,467	)	22.17		-	24.41		24.32
Balance at December 31, 2015	550,402		$	22.52	-	$	25.07	$	24.01

Transactions involving restricted shares under the terms of the LTSIP for the year ended December 31, 2015, are summarized below:

	Restricted Shares Outstanding		Price Range					Weighted- Average Price
Balance at December 31, 2014	102,354		$	19.39	-	$	21.53	$	19.41
Vested	(102,135	)	19.39		-	21.53		19.40
Balance at December 31, 2015	219		$	21.53	-	$	21.53	$	21.53

Calculated fair value of performance shares granted and major assumptions used in the Monte Carlo simulation

The estimated fair value of performance shares granted and major assumptions used in the simulation at the date of grant are listed below:

	2015			2014			2013
	Performance Share Input Variables
Fair value of performance shares at grant date	$	21.03		$	31.07		$	39.62
Risk-free interest rate	0.95		%	0.67		%	0.40		%
Expected price volatility	16.1		%	18.6		%	19.0		%
Expected dividend yield	3.11		%	3.05		%	2.88		%
Expected life in years	2.9			2.9			2.9

Transactions involving performance shares under the terms of the LTSIP

Transactions involving performance shares under the terms of the LTSIP for the year ended December 31, 2015, are summarized below:

	Target Number of Performance Shares Outstanding		Grant-Date Fair Value Range					Weighted-Average Grant-Date Fair Value
Balance at December 31, 2014	391,249		$	25.42	-	$	39.62	$	31.78
Granted	160,302		19.03		-	21.03		20.82
Distributed(1)	(134,778	)	25.42			25.42		25.42
Forfeited	(73,025	)	21.03		-	39.62		26.11
Balance at December 31, 2015(2),(3)	343,748		$	19.03	-	$	39.62	$	30.37

⁽¹⁾ Actual shares and cash distributed were determined by multiplying the target shares by 1.00 to reflect Questar's final total shareholder return ranking relative to the specified peer companies for the performance period from January 1, 2012 through December 31, 2014. The total amount paid for the cash half of the distribution was $1.7 million.

⁽²⁾ The total undistributed balance consists of 286,211 of share-settled target shares and 57,537 of cash-settled target shares.

⁽³⁾ The total undistributed balance includes 115,074 vested target shares that are expected to be distributed in the first quarter of 2016 using a payout adjustment multiplier of 0.32. The multiplier reflects Questar's final total shareholder return ranking relative to the specified peer companies for the performance period from January 1, 2013 through December 31, 2015. The distribution will be half in shares, half in cash. These target shares are included in the amounts described in note (2), immediately above.

Questar Pipeline and Questar Gas [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Options held under the LTSIP, by exercise price range

The following table summarizes the stock options held under the LTSIP by Questar Pipeline officers and employees at December 31, 2015. There were no stock options held under the LTSIP by Questar Gas officers or employees at December 31, 2015.

Options Outstanding									Options Exercisable
Range of exercise prices					Number outstanding at Dec. 31, 2015	Weighted-average remaining term in years	Weighted-average exercise price		Number exercisable at Dec. 31, 2015	Weighted-average exercise price
Questar Pipeline
$	11.40	-	$	13.10	47,995	0.5	$	11.98	47,995	$	11.98

Transactions involving restricted shares and RSUs under the terms of the LTSIP

There were no restricted shares held under the LTSIP by Questar Gas and Questar Pipeline officers and employees at December 31, 2015.

The following table summarizes the RSUs held under the LTSIP by Questar Gas and Questar Pipeline officers and employees at December 31, 2015. The weighted-average remaining vesting periods of unvested RSUs at December 31, 2015, for Questar Gas and Questar Pipeline were 10 months and 11 months, respectively.

	RSUs Outstanding	Price Range					Weighted-Average Price
Questar Gas	97,209	$	23.09	-	$	24.41	$	24.01
Questar Pipeline	126,744	$	23.09	-	$	24.41	$	23.95

Transactions involving performance shares under the terms of the LTSIP

The following table summarizes the target number of performance shares held under the LTSIP by Questar Gas and Questar Pipeline officers at December 31, 2015. The weighted-average remaining vesting periods of unvested performance shares at December 31, 2015, for Questar Gas and Questar Pipeline were 18 months and 23 months.

	Target Number of Performance Shares Outstanding	Grant-Date Fair Value Range					Weighted-Average Grant-Date Fair Value
Questar Gas	33,578	$	21.03	-	$	39.62	$	30.23
Questar Pipeline	47,454	$	19.03	-	$	39.62	$	28.43